Book of Abstracts€¦ · 25th International Nuclear Physics Conference (INPC 2013), Firenze (Italy), 2-7 June 2013

Book of Abstracts

09 – Hadrons in Nuclei

25th International Nuclear Physics Conference (INPC 2013), Firenze (Italy), 2-7 June 2013

Foreword

In the present booklet we have collected the one-page abstracts of all contributions (invited, oral and poster) accepted at the INPC2013 Conference in the topic

Hadrons in Nuclei

The submitted abstracts have been divided into the various topics of the Conference following mostly the indication given by the authors. In few cases, where the subject was on the borderline of two scientific areas or it appeared misplaced, the abstracts have been moved to the booklet of the more appropriate topic.

The abstracts are numbered and arranged alphabetically according to the name of the first author. In the parallel and poster sessions of the Conference, each contribution will be identified by the number of the corresponding abstract.

We wish you a pleasant and stimulating Conference.

The Organizing Committee

Hadrons in Nuclei (HN)

HN 001. Experimental results on antiproton–nuclei annihilation cross section at very low energies H. Aghai-Khozani, D. Barna, M. Corradini, R. Hayano, M. Hori, T. Kobayashi, M.Leali, E. Lodi-Rizzini, V. Mascagna, M. Prest, A. Soter, K. Todoroki, E.Vallazza, L.Venturelli, N. Zurlo Contact email: [email protected]

HN 002. Study of the Λ(1116) interaction in cold nuclear matter O. Arnold Contact email: [email protected]

HN 003. Photoproduction of Λ from the deuteron near the threshold B. Beckford, P. Bydžovský, A. Chiba, D. Doi, T. Fujii, Y. Fujii, K. Futatsukawa, T. Gogami, O. Hashimoto, Y.C. Han, K. Hirose, S. Hirose, R. Honda, K. Hosomi, T. Ishikawa, H. Kanda, M. Kaneta, Y. Kaneko, S. Kato, D. Kawama, C. Kimura, S. Kiyokawa, T. Koike, K. Maeda, K. Makabe, M. Matsubara, K. Miwa, S. Nagao, S. N. Nakamura, A. Okuyama, K. Shirotori, K. Sugihara, K. Suzuki, T. Tamae, H. Tamura, K. Tsukada, K. Yagi, F. Yamamoto, T. O. Yamamotoi, H. Yamazaki, and Y. Yonemoto Contact email: [email protected]

HN 004. Neutral Kaons in Cold Nuclear Matter J. Berger-Chen Contact email: [email protected]

HN 005. Neutron-rich Λ-Hypernuclei study with the FINUDA experiment E. Botta Contact email: [email protected]

HN 006. Unveiling the strangeness secrets: low-energy kaon-nucleon/nuclei interaction studies at DAΦNE Catalina Curceanu Contact email: [email protected]

HN 007. Angular Distribution of ρ meson in the (γ,ρ) Reaction Swapan Das Contact email: [email protected]

HN 008. ρ meson Nucleus Optical Potential in the GeV Region Swapan Das Contact email: [email protected]

HN 009. Search of strange multi-baryons in the hadronic decays of ϒ(nS) F. De Mori, A. Filippi, S. Marcello Contact email: [email protected]

HN 010. Light nuclei and hyper-nuclei from lattice QCD W. Detmold Contact email: [email protected]

HN 011. New approach to investigation of nuclei E. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova Contact email: [email protected]

HN 012. The role of two-nucleon mechanisms in pion photoproduction on nuclei in the region of high momentum transfer M.Egorov, A. Fix Contact email: [email protected]

HN 013. Spectroscopy of η′ Mesic Nuclei via Semi-Exclusive Measurement at FAIR H. Fujioka, K. Itahashi, S. Friedrich, H. Geissel, R. S. Hayano, S. Hirenzaki, S. Itoh, D. Jido, V. Metag, H. Nagahiro, M. Nanova, T. Nishi, K. Okochi, H. Outa, K. Suzuki, T. Suzuki, Y. K. Tanaka, and H. Weick Contact email: [email protected]

HN 014. Dynamics of multi-Λ hypernuclei in antiproton-induced reactions T. Gaitanos, A.B. Larionov, H. Lenske, U. Mose Contact email: [email protected]

HN 015. Neutron-rich hypernuclei beyond Λ6H A.Gal, D.J. Millener Contact email: [email protected]

HN 016. High-Resolution Hypernuclear Spectroscopy at JLab Hall A. Results and perspectives Franco Garibaldi Contact email: [email protected]

HN 017. π − 4He interactions in the ∆ resonance energy region I. Gnesi Contact email: [email protected]

HN 018. A search for the K-pp bound state in the 3He(inflight-K-,n) reaction at J-PARC T. Hashimoto Contact email: [email protected]

HN 019. Structure of Be hyper isotopes M. Isaka, H. Homma, M. Kimura Contact email: [email protected]

HN 020. Excited states with Λ hyperon in p orbit in 𝑀𝑔Λ25

M. Isaka, M. Kimura, A. Dote and A. Ohnishi Contact email: [email protected]

HN 021. Feasibility Study of Pionic Atom Spectroscopy with Unstable Nuclei K. Itahashi, H. Fujioka, R.S. Hayano, T. Nishi, K. Okochi, Y.K. Tanaka, Y.N. Watanabe Contact email: [email protected]

HN 022. RIKEN’s activity at J-PARC Hadron Hall M. Iwasaki Contact email: [email protected]

HN 023. Nonmesonic weak decay of light hypernuclei within soft π + K meson-exchange model Franjo Krmpotić Contact email: [email protected]

HN 024. Search for the η-mesic 4He with WASA-at-COSY W. Krzemien, P. Moskal, J. Smyrski and M. Skurzok Contact email: [email protected]

HN 025. Manifestation of multibaryons in hadronic collisions at intermediate energies V.I. Kukulin, M.N. Platonova Contact email: [email protected]

HN 026. Spectroscopy of the Hadronic Atoms: K-N Strong Interaction Effects A.S. Kvasikova, T.A. Florko and D.E. Sukharev Contact email: [email protected]

HN 027. Hypernucleus production in heavy ion collision - a theoretical analysis A.LeFèvre, Y. Leifels, C. Hartnack, J.Aichelin Contact e-mail: [email protected]

HN 028. Hadronization in Nuclei – Recent Multidimensional Results from HERMES Inti Lehmann Contact email: [email protected]

HN 029. Antiproton-Nucleus Interactions and Meson Production on Complex Nuclei H. Lenske, S. Lourenço, S. Wycech Contact email: horst.lenskephysik.uni-giessen.de

HN 030. Shape evolution of Ne isotopes and Ne hypernuclei: The interplay of pairing and tensor interactions A.Li, E. Hiyama, X.-R. Zhou, H.Sagawa Contact email: [email protected]

HN 031. First measurement of low momentum dielectrons radiated off cold nuclear matter Manuel Lorenz Contact email: [email protected]

HN 032. Charmonium photoproduction in coherent and incoherent heavy ion collisions at the LHC M.V.T. Machado Contact email: [email protected]

HN 033. Measurements of the 2H(, n) breakup reaction at 170MeV for the study of the three-nucleon force effects Y. Maeda, T. Saito, H. Miyasako, T. Uesaka, S. Ota, S. Kawase, T. Kikuchi, H. Tokieda, T.Kawabata, K. Yako, T. Wakasa, S. Sakaguchi, R. Chen, H. Sakaguchi, T. Shima, T. Suzuki, A. Tamii Contact email: [email protected]

HN 034. Calculations of 𝐾 nuclear quasi-bound states using chiral 𝐾N amplitudes J. Mareš, N. Barnea, A. Cieplý, E. Friedman, A. Gal, D. Gazda Contact email: [email protected]

HN 035. Microscopic Investigation of the Structure Characteristics and Wave functions of the Five-Body Hypernucleus 𝐻λ5 Lia Leon Margolin Contact email: [email protected]

HN 036. J-PARC Experiment (E07) to Study Double Hypernuclei K. Nakazawa Contact email: [email protected]

HN 037. Determination of the η’-nucleus optical potential Mariana Nanova Contact email: [email protected]

HN 038. The first precision measurement of deeply bound pionic states in 121Sn T. Nishi , G.P.A. Berg, M. Dozono, H. Fujioka, N. Fukuda, T. Furuno, H. Geissel, R.S. Hayano, N. Inabe, K. Itahashi, S. Itoh, D. Kameda, T. Kubo, H. Matsubara, S. Michimasa, K. Miki, H. Miya, Y. Murakami, M. Nakamura, N. Nakatsuka, S. Noji, K. Okochi, S. Ota, H. Suzuki, K. Suzuki, M. Takaki, H. Takeda, Y.K. Tanaka, K. Todoroki, K. Tsukada, T. Uesaka, Y.N. Watanabe, H. Weick, H. Yamada, and K. Yoshida Contact email: [email protected]

HN 039. New interpretation of the ABC effect in the basic double-pionic fusion reaction M.N. Platonova, V.I. Kukulin Contact email: [email protected]

HN 040. Search for H-dibaryon at J-PARC with a Large Acceptance TPC H. Sako, J. K. Ahn, S. H. Kim, S. J. Kim, S. Y. Kim, A. Ni, J. Y. Park, S. Y. Ryu, S. H. Hwang, S. Hasegawa, R. Honda, Y. Ichikawa, K. Imai, S. Sato, K. Shirotori, S. Sugimura, H. Fujioka, M. Niiyama, R. Kiuchi, Tanida. Ieiri, K. Ozawa, H. Takahashi, T. Takahashi, K. Nakazawa, M. Sumihara, B. Bassalleck Contact email: [email protected]

HN 041. Spectroscopy of the Pionic Atoms: Energy Shifts and Widths and π-N Strong Interaction Effects A.N. Shakhman and I.N. Serga Contact email: [email protected]

HN 042. The yield of kaonic hydrogen X-rays in SIDDHARTA experiment H. Shi, M. Bazzi, G. Beer, C. Berucci, L. Bombelli, A.M. Bragadireanu , M. Cargnelli, A. Clozza, C. Curceanu, A. d’Uffizi, C. Fiorini, F. Ghio, C. Guaraldo, R. S. Hayano, M. Iliescu, T. Ishiwatari, M. Iwasaki, P. Kienle, P. Levi Sandri, V. Lucherini, J. Marton, S. Okada, D. Pietreanu, K. Piscicchia, M. Poli Lener, T. Ponta, R. Quaglia, A. Romero Vidal, E. Sbardella, A. Scordo, D.L. Sirghi, F. Sirghi, H. Tatsuno, A. Tudorache, V. Tudorache, O. Vazquez Doce, E. Widmann, B. Wünschek, J. Zmeskal Contact email: [email protected]

HN 043. Search for 4He-η bound states in dd → (4He-η)bs →3Hepπ- and dd → (4He-η)bs → 3Henπ0 reactions with the WASA-at-COSY facility. M. Skurzok, W. Krzemien, P. Moskal Contact email: [email protected]

HN 044. Study on 𝐻ᴧ6 hypernucleus by the (π-;K+) reaction at J-PARC H. Sugimura, M. Agnello, J. K. Ahn, S. Ajimura, Y. Akazawa, N. Amano, K. Aoki, H. C. Bhang, M. Endo, P. Evtoukhovitch, A. Feliciello, H. Fujioka, T. Fukuda, S. Hasegawa, S. Hayakawa, R. Honda, K. Hosomi, S. H. Hwang, Y. Ichikawa, Y. Igarashi, K. Imai, N. Ishibashi, R. Iwasaki, C. W. Joo, R. Kiuchi, J. K. Lee, J. Y. Lee, K. Matsuda, Y. Matsumoto, K. Matsuoka, K. Miwa, Y. Mizoi, M. Moritsu, T. Nagae, S. Nagamiya, M. Nakagawa, M. Naruki, H. Noumi, R. Ota, B. J. Roy, P. K. Saha, A. Sakaguchi, H. Sako, C. Samanta, V. Samoilov, Y. Sasaki, S. Sato, M. Sekimoto, Y. Shimizu, T. Shiozaki, K. Shirotori, T. Soyama, T. Takahashi, T. N. Takahashi, H. Tamura, K. Tanabe, T. Tanaka, K. Tanida, A. O. Tokiyasu, Z. Tsamalaidze, M. Ukai, T. O. Yamamoto, Y. Yamamoto, S. B. Yang, K. Yoshida Contact email: [email protected]

HN 045. Formation of strange dibaryon X(2265) in p+ p → K+ + X reaction at Tp = 2.5 and 2.85 GeV K. Suzuki, P. Kienle, M. Maggiora, T. Yamazaki Contact email: [email protected]

HN 046. Missing Mass Spectroscopy of η’ Mesic Nuclei with (p, d) Reaction at GSI Y. K. Tanaka, K. Itahashi, H. Fujioka, S. Friedrich, H. Geissel, R. S. Hayano, S. Hirenzaki, S. Itoh, D. Jido, V. Metag, H. Nagahiro, M. Nanova, T. Nishi, K. Okochi, H. Outa, K. Suzuki, T. Suzuki, Y. N. Watanabe, and H. Weick Contact email: [email protected]

HN 047. Beam diagnostics for measurements of antiproton annihilation cross sections at ultra-low energy K. Todoroki, H. Aghai-Khozani, D. Barna, M. Corradini, M. Hori, R. Hayano, T. Kobayashi, M. Leali, E. Lodi-Rizzini, V. Mascagna, M. Prest, A. Soter, E. Vallazza, L. Venturelli, and N. Zurlo Contact email: [email protected]

HN 048. Six-body calculations for hyperhydrogen 𝐻λ6 Sh. Tsiklauri Contact email: [email protected]

HN 049. p d→3He η reaction beyond threshold energies N. J. Upadhyay, B. K. Jain Contact email: [email protected]

HN 050. Structure of low-lying spectrum of cluster αnΛ system B.Vlahovic, V.M. Suslov, I. Filikhin Contact email: [email protected]

HN 051. Charmonium-Nucleus Bound States A.Yokota, E. Hiyama, M. Oka Contact email: [email protected]

International Nuclear Physics Conference INPC2013: 2-7 June 2013, Firenze, Italy

Experimental results on antiproton–nuclei annihilation cross section atvery low energies

H. Aghai-Khozani1,2 , D. Barna3,4, M. Corradini5,6, R. Hayano4, M. Hori1,4, T. Kobayashi4, M.Leali5,6, E. Lodi-Rizzini5,6, V. Mascagna5, M. Prest7,8, A. Soter1, K. Todoroki4, E. Vallazza9, L.

Venturelli5,6, N. Zurlo5,6

1 Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany2 Physics Department, CERN, 1211 Geneva 23, Switzerland

3 Wigner Institute for Particle and Nuclear Physics, H-1525 Budapest, Hungary4 Department of Physics, University of Tokyo. Tokyo 113-0033, Japan

5 Dipartimento di Ingegneria dell’Informazione, Universita di Brescia, I-25123 Brescia, Italy6 Istituto Nazionale di Fisica Nucleare, Gruppo Collegato di Brescia, I-25123 Brescia, Italy

7 Universita degli Studi dell’Insubria, I-22100 Como,Italy8 Istituto Nazionale di Fisica Nucleare, Sezione di Milano Bicocca, I-20126 Milano, Italy

9 Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste, Italy

Contact email:[email protected]

Investigating the antiproton cross section on nuclei at low energies (1 eV – 1 MeV) is of great interestfor fundamental cosmology and nuclear physics as well.

The process is of great relevance for the models which try to explain the matter/antimatter asymmetryin the universe assuming the existence of the so-called “island” where antinucleon-nucleon annihilationsoccur in the border region [1]. For the nuclear physics point of view, the annihilation process is con-sidered a useful tool to evaluate the neutron/proton ratio probing the external region of the nucleus.Moreover, the cross section measured at LEAR in the 80s–90s showed an unexpected behaviour for en-ergies below 1 MeV. The results showed a saturation with the atomic mass number against the A2/3 trendwhich is known for higher energies.

The ASACUSA collaboration at CERN measured 5.3 MeV antiproton in-flight annihilation crosssection on different nuclei whose results demonstrated to be consistent with the black-disk model withthe Coulomb correction [2]. So far, experimental limits prevented the data acquisition for energies below1 MeV. In 2012 the 100 keV region has been investigated for the first time [3].

We present here the results of the experiment.

[1] A. G. Cohen, A. de Rujula and S. L. Glashow, The Astrophys. Journ. 495 (1998), 539;[2] A. Bianconi et al., Phys. Lett. B 704, (2011) 461;[3] H. Aghai-Khozani et al., Eur. Phys. J. Plus (2012) 127: 125.

HN 001


Study of the Λ(1116) interaction in cold nuclear matterO. Arnold1

1 Excellence Cluster ’Universe’, Technical University of Munich, D–85748, Garching, Germany

Contact email: [email protected]

The stiffness of nuclear matter in the interior of neutron stars is still an open question. The ap-pearance of Λ(1116)-hyperons inside the star might lead to a soft equation of state due to the attractiveΛ-hyperon potential. With the recent finding and precise measurement of a two solar mass neutron star,new constraints are available to examine this hypothesis. An important parameter which enters sometheoretical models underlying nuclear equations of state is the strength of the hyperon potential.To determine the value of the in-medium Λ interaction strength in cold nuclear matter at ground statedensity, we interpret the HADES results on Λ production in proton-niobium collisions at a beam kineticenergy of 3.5 GeV. The comparison with different transport models allows us to extract the interactionstrength. In this context we discuss the influence of various parameters entering the transport model(such as production and scattering cross-sections) with help of the GiBUU code.

HN 002


Photoproduction of Λ from the deuteron near the thresholdB. Beckford1, P. Bydzovsky2, A. Chiba1, D. Doi1, T. Fujii1, Y. Fujii1, K. Futatsukawa1,

T. Gogami1, O. Hashimoto1, Y.C. Han3 ,K. Hirose2, S. Hirose 1, R. Honda1, K. Hosomi1,T. Ishikawa2, H. Kanda1, M. Kaneta1, Y. Kaneko1, S. Kato1, D. Kawama1, C. Kimura1

S. Kiyokawa1, T. Koike1, K. Maeda1, K. Makabe1, M. Matsubara1, K. Miwa1, S. Nagao1,S. N. Nakamura1, A. Okuyama1, K. Shirotori1, K. Sugihara1, K. Suzuki2, T. Tamae2, H. Tamura1,

K. Tsukada1, K. Yagi1, F. Yamamoto1, T. O. Yamamotoi1, H. Yamazaki1, and Y. Yonemoto1

1 Department of Physics, Tohoku University, Sendai 9808578, Japan2 Research Center for Electron Photon Science, Tohoku University, Sendai, 982-08263 School f Nuclear Science and Technology, Lanzhou University, Lanzhou, 730000

4 Nuclear Physics Institute, Rez near Prague, Czech Republic, 25068


The electromagnetic production of strange meson and baryons continues to be a growing topic in morerecent years due in part to the continual increase of beam energy at accelerator facilities. It is well knownthat production of strangeness on nucleons provides details about hadronic structures including formfactors. With the limited available data for the neutral channel our efforts were placed there. In thisreport we present results on cross sections for Λ in the γd → ΛX reaction measured at the ResearchCenter for Electron Photon Science (ELPH) at tagged photon energies between 0.8 ≤ Eγ ≤ 1.1 GeV.The experiment was successfully performed using the Neutral Kaon Spectometer (NKS2+) where theproduced Λ was measured by exploiting the pπ− decay channel. Momentum and angular distributionsin the laboratory frame were measured in addition to the integrated cross sections for forward Λ scat-tering angles. From integrated measurements of Λ from γd, total cross sections of γd → K0Λp wereestimated. Results were compared to theoretical calculations, where the Saclay-Lyon A (SLA) [1] andRegge-Plus-Resonance (RPR-2007) model [2] calculations compared favorably to the data.

[1] T. Mizutani, C. Fayard, G. H. Lamot, and B. Saghai. Phys Rev. C 58,75 (1998).[2] P. Vancraeyveld et.al. Nucl. Phys. A 897,42 (2013).

HN 003


Neutral Kaons in Cold Nuclear MatterJ. Berger-Chen1

1 Excellence Cluster Universe, Technical University of Munich, 85748 Garching, Germany


Since the recent discovery of a massive neutron star of 1.97 solar masses [1] the discussion about a pos-sible existence of a condensed kaon matter inside the neutron star has been revived [2,3]. Kaons notonly influence the nuclear EOS [1,2], but also play an important role for the cooling process of a neutronstar [4]. Thus a better understanding of the kaon nucleon/nucleus interaction is urgently requested. Forexample, characteristics of the interaction such as the KN potential and the KN scattering in medium stillneed further investigation.

By studying proton and pion induced reactions a potential strength of UKN (ρ0) ≈ +20 MeV was ex-tracted from comparisons of kaon momentum distributions with transport calculations [6,7]. In contrasta potential of UKN (ρ0) ≈ +40 MeV was deduced from a heavy ion experiment, thus providing a puzzleabout the exact strength of the KN potential [5]. One of the possible reasons is the unsufficient knowledgeof in-medium KN scattering. In order to pin down the respective cross section more high quality data areneeded.

In this contribution we present high statisticsK0S data from p+p and p+93Nb collisions atEkin = 3.5 GeV

obtained with the HADES detector at GSI. The p+p data serve as the reference for the proton+nucleusdata. Good statistics in both data sets allow differential analysis in pt-y and angular distributions inmomentum bins. As in-medium effects, such as the KN potential and the KN scattering cross sections,will be extracted from p+93Nb analysis with the help of transport models, a good description of thep+p data by the models is required. Therefore, production cross sections of single reactions (e. g.p + p → Y + ∆++ + K0, p + p → Y + p + π+ + K0) are needed as a constraint for the transportmodels. Results of the ongoing investigation will be presented in the contribution.

[1] P.B. Demorest et al., Nature 467, 10811083 (2010);[2] K. Masuda et al., arXiv:1205.3621[nucl-th] (2012);[3] K. Kim et al., Phys. Rev. C 84, 035810 (2011);[4] S. Kubis et al., Nucl. Phys. A, 720 189-206 (2003);[5] G. Agakishiev et al., Phys. Rev. C 82, 044907 (2010);[6] M. Buscher et al., Eur. Phys. J. A 22, 301-317 (2004);[7] M.L. Benabderrahmane et al., PRL 102, 182501 (2009).

HN 004

Neutron-rich Λ-Hypernuclei study with the FINUDA experiment

E. Botta

INFN - Sezione di Torino and Torino University - Physics Department via P. Giuria 1, Torino, Italy

Λ-hypernuclei are long lived systems in which the Λ hyperon acts as constituent nucleon.The strangeness degree of freedom of the hyperon makes the Pauli exclusion principle inef-fective on it and allows the Λ to populate sharp single particle shell model states down tothe Λ(1s) ground state.

In Λ-hypernuclei, then, a strong contribution to the total binding energy is added bythe Λ, with the possibility of producing bound systems containing unstable core nuclei(glue-like role of the Λ). Λ-hypernuclei are thus suitable tools for investigating neutron-rich(proton-rich) systems, even beyond the neutron (proton) drip line.

The study of neutron-rich Λ-hypernuclei is one the main topics of the scientific programof the FINUDA experiment which has completed its operation at DAΦNE, the INFN-LNF(e+, e−) collider working at the Φ(1020) center of mass energy. FINUDA has performedan extensive search for bound neutron-rich Λ-hypernuclear states. In the first data taking(2003-2004), 6

ΛH, 7ΛH and 12

Λ Be have been investigated by looking at the π+ from the doublecharge exchange (K−

stop, π+) production reaction; upper limits for the production rates

have been reported [1]: Rπ+(6ΛH) < (2.5 ± 0.4stat

+0.4−0.1syst) · 10−5/K−

stop, Rπ+(7ΛH) < (4.5 ±

0.9stat+0.4−0.1syst) · 10−5/K−

stop and Rπ+(12ΛBe) < (2.0 ± 0.4stat

+0.3−0.1syst) · 10−5/K−

stop.In the second data taking (2006-2007) a ∼5 times larger statistics has been collected

and a new analysis technique has been applied for the search of bound 6ΛH and 9

ΛHe, basedon the coincidence between a π+ from the (K−

stop, π+) production reaction and a π− from

the two body mesonic weak decay of the hypernucleus to π− +6 Heg.s.. With this methodthe existence of 6

ΛH as a bound state has been assessed, based on 3 clearly identified events,with a binding energy BΛ=(4.0±1.1) MeV, with respect to 5H+Λ; and a production rateRπ+(6

ΛH)= (5.9±4.0)·10−6/K−stop [2,3] has been evaluated. Indications on the structure of

the 6ΛH energy levels have been obtained from a systematic difference among the 6

ΛH massevaluated from production and decay reactions.

The same method has been applied to the search for bound 9ΛHe, which is interesting

since it could be a neutron-halo Hypernucleus. No event was found and an upper limit forits production, Rπ+(9

ΛHe)¡(5.0±4.1) ·10−6/K−stop, was deduced [4].

In the presentation a review of all observed neutron-rich Λ-hypernuclei will be given,with particular emphasis on the FINUDA results and on their discussion.

[1] M. Agnello, et al., Physics Letters B 640 (2006) 145.

[2] M. Agnello et al., Physical Review Letters 108 (2012) 042501.

[3] M. Agnello et al., Nuclear Physics A 881 (2012) 269.

[4] M. Agnello et al., Physical Review C 86 (2012) 057301.


International Nuclear Physics Conference INPC2013: 2-7 June 2013, Firenze, ItalyHN 005


Unveiling the strangeness secrets:

low-energy kaon-nucleon/nuclei interaction studies at DAΦNE

Catalina Curceanu On behalf of the SIDDHARTA, SIDDHARTA-2 and AMADEUS Collaborations

Laboratori Nazionali di Frascati dell’INFN, Via E. Fermi 40, 00044 Frascati (Roma), Italy


The low-energy QCD in the strangeness sector is still lacking fundamental experimental results in order to arrive to a breakthrough in its understanding. Part of this information is provided by the low-energy kaon-nucleon/nuclei interaction studies, both as kaonic atoms and nuclear processes.

Combining the excellent quality kaon beam of the DAΦNE collider with new experimental techniques, as fast and very precise X ray detectors like the Silicon Drift Detectors and almost full acceptance detector of charged and neutral particles as KLOE, we have performed unprecedented measurements in the framework of SIDDHARTA and AMADEUS Collaborations.

The kaonic atoms, as kaonic hydrogen and kaonic deuterium, provide the isospin dependent kaon-nucleon scattering lengths from the measurement of X rays emitted in the de-excitation process to the fundamental 1s level of the excited formed atom. The most precise kaonic hydrogen measurement was performed by the SIDDHARTA collaboration, which realized, as well, the first exploratory measurement for kaonic deuterium ever. Additional important measurements of more complex systems, as kaonic helium 3 and kaonic helium 4 were as well done (the kaonic helium 3 was measured for the first time as well). Presently, a major upgrade of the setup, SIDDHARTA-2 is ready to perform in the near future a precise measurement of kaonic deuterium and other exotic atoms.

The kaon – nuclei interactions are being measured by the AMADEUS collaboration for kaon momenta smaller than 100 MeV/c by using the KLOE detector implemented in the central region with a dedicated setup. Preliminary results for the interaction of negatively charged kaons with various type of nuclei will be shown, including an analyses of the mysterious Λ(1405). Future plans will be discussed.

DAΦNE, with SIDDHARTA, SIDDHARTA-2 and AMADEUS, represents an opportunity which is unique in the world to, finally, unlock the secrets of the QCD in the strangeness sector, with important consequences going from particle and nuclear physics to astrophysics.

HN 006


Angular Distribution of meson in the ( ,) Reaction

Swapan Das

Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India


We calculate the angular distribution of the meson produced in the ( ,) reaction on 12C nucleus. This meson is probed by the dielectron emission at Jefferson Laboratory [1] for its momentum range: k(GeV/c) = 0.8-3.0. Since the kinetic energy of the meson is much higher than its potential energy, we approximate the propagation this meson by the eikonal form [2]:

G(r/-r) = (b/-b) (z/-z) exp [i k (r/-r)] D, (1)

where D is given by

−−=

−/

),(2)(~

2

exp2

//10

//z

z

O zbVEmGdzk

i

k

iD ρρρ

ρρρ (2)

with )()(~ 221

0 mimmmmG ρρρρ Γ+−=− . The symbols carry their usual meanings. VO is the meson

nucleus optical potential which can be obtained by folding the elementary meson nucleon t-matrix with the nuclear density distribution [2].

We plot in figure 1 the calculated angular distribution of the meson. This figure shows that the meson of momentum 0.8 to 3.0 GeV/c is emitted distinctly in the forward direction.

θρ (deg)

0 5 10 15

d σ/d

mdc

osθ ρ

(nb/

GeV

)

0

20

40

60

8012C(γ,ρ0 e+e- )12Ckρ (GeV/c)=0.8-3.0

m =770 MeV

Figure 1: Angular distribution of the meson for its momentum k (GeV/c)=0.8-3.0.

[1] R. Nasseripour et. al., (CLAS Collaboration), Phys. Rev. Lett. 99, 262302 (2007); M. H. Wood et. al., (CLAS Collaboration), Phys. Rev. C 78, 015201 (2008); [2] Swapan Das, Phys. Rev. C 72, 064619 (2005); ibid, 83, 064608 (2011).

HN 007


meson Nucleus Optical Potential in the GeV Region

Swapan Das

Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai-400085, India


We calculate the momentum dependent meson nucleus optical potential which can modify the hadronic parameters of the meson in the nucleus. This potential can be obtained by folding the elementary meson nucleon t-matrix with the nuclear density distribution [1], i.e.,

2

1−= v

where v is the velocity of the meson. is the ratio of the real to imaginary part of the meson nucleon scattering amplitude . is the corresponding total cross section. In the GeV region, these quantities can be extracted from the elementary meson photoproduction ( ) data [2]. In fact, the vector meson dominance model relates the reaction amplitude f to [2].

represents the nuclear density distribution, obtained from the electron nucleus scattering data [3].

We evaluate the real and imaginary parts of the meson optical potential for 0.17 fm-3 in the meson 12C cm system. In figure below, we show them for the meson momentum k lying between 0.8 to 3 GeV/c.

kρ (GeV/c)

0.5 1.0 1.5 2.0 2.5 3.0

ReV

Oρ

(MeV

)

0

10

20

30

40

50

kρ (GeV/c)

0.5 1.0 1.5 2.0 2.5 3.0

ImV

Oρ

(MeV

)

-100

-80

-60

-40

-20

0

Figure 1: Variation of the meson optical potential with its momentum.

[1] Swapan Das, Phys. Rev. C 83, 064608 (2011); [2] L. A. Kondratyuk et al., Phys. Rev. C 58, 1078 (1998); [3] C. W. De Jager et al, At. Data Nucl. Data Tables 14, 479 (1974).

HN 008


Search of strange multi-baryons in the hadronic decays of Υ(nS)

F. De Mori1, A. Filippi2, S. Marcello1

1 Dipartimento di Fisica, Universita di Torino and INFN, Sezione di Torino, Torino, Italy2 INFN, Sezione di Torino, Torino, Italy


The baryonic production in the hadronic decays of Υ(nS) has been found enhanced of about a factor oftwo relative to the continuum hadronization by CLEO [1] and previous experiments due to the dominantdecay of Υ(1S) to ggg and ggγ (B.R. 80%).Measurements of antideuteron production in Υ(nS, n=1, 2,3,4) resonance decays and in the nearby con-tinuum had been performed by ARGUS [2] and CLEO [3]. In this case the experimental data seem tofavor a coalescence mechanisms for this production.These results encourage to search [4] for slightly more complex baryons in the hadronic decay of Υ, likeΛ(1405) or possible strange multi-baryonic clusters (as K−NN) whose existence is still debated.The B factories represent an environment completely different from those in which these searches havebeen carried out up to now [5] and the observation of a signature of these states could cast new light onthe understanding of strange nuclear matter. The possibility of such a search will be presented in thistalk.

[1] R.A. Briere et al. (CLEO Collaboration), Phys. Rev. D76, 012005 (2007);[2] H. Albrecht et al. (ARGUS Collaboration), Phys. Lett. B 236, 102 (1990);[3] D.M. Asner et al. (CLEO Collaboration), Phys. Rev. D75, 012009 (2007);[4] S. Marcello, F. De Mori, A. Filippi, http://arxiv.org/abs/1212.2158 (2012);[5] M. Agnello et al. (FINUDA Collaboration), Phys. Rev. Lett. 94, 212303 (2005);

HN 009


Light nuclei and hyper-nuclei from lattice QCD

W. Detmold1

1 Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA


Theoretical nuclear physics is undergoing a transition, in which the long promised connection to the underlying Standard Model is beginning to be explored quantitatively using the lattice field theory methods. Growth in the available computational resources and significant advances in algorithms have made it possible to study light nuclei and hyper-nuclei directly from QCD for the first time [1], albeit at quark masses heavier than those in nature. In addition, the low-energy nucleon-nucleon scattering phase shifts have also been extracted from lattice QCD calculations [2], paving the way for the investigation of more complex systems. I will summarize the calculational approach, present recent results of ongoing studies, and outline the impact and future directions of these calculations.

[1] Beane, S.R. et al., Phys. Rev. D 87, 034506 (2013). [2] Beane, S.R. et al., arXiv:1301.5790.

HN 010


NEW APPROACH TO INVESTIGATION OF NUCLEIE. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova

Petersburg Nuclear Physics Institute NRC “Kurchatov Institute”, St. Petersburg 188300, Russia


It is well known that the standard approach to description of nucleon in nuclear matter, based on theconception of interaction between the point-like nucleons faces many problems connected with the shortdistances. On the other hand the strong interactions are known to become increasingly simple at shortdistances due to the asymptotic freedom of the Quantum Chromodynamics (QCD). It is tempting to usethis feature of the QCD in building the nuclear forces. Our approach is based on extension of the QCDsum rules (SR) method in vacuum [1] to the systems with finite density of the baryon quantum number.It is based on the dispersion relations for the function, describing the space-time propagation of thesystem which carries the quantum numbers of the hadron. Due to the asymptotic freedom of the QCD itbecame possible to connect the strong interactions at the distances of the order of the confinement radiuswith those at much smaller distances, where the interactions are determined by the QCD condensates.Thus we expect that the parameters of the nucleon in nuclear matter can be expressed in terms of thein-medium values of the QCD condensates.

The generalization of the SR method for the case of the nucleon in nuclear matter which was startedin [2]was not straightforward. One of the main problems was the choice of the variables which enabled toseparate the singularities connected with the in-medium nucleon from those connected with the mediumitself. Dependence of the Dirac effective massm∗ and the vector self energy Σv on the QCD condensatesof the lowest dimension d = 3 (the vector and scalar ones) was found. The vector condensate wascalculated, it is proportional to the nuclear density ρ. The linear part of the scalar condensate (shown tobe the most important part close to the saturation density) was presented in terms of the pion-nucleonσ-term which can be expressed in terms of the amplitude of elastic πN scattering. The SR approachprovided reasonable values for m∗ and Σv at the phenomenological value of the saturation density.

These results were not altered by inclusion of the higher condensates which were calculated in frame-work of relativistic quark models of the nucleon. The four-quark condensates beyond the gas approxi-mation provided the three-nucleon forces in a natural way. Thus we calculated the nucleon self-energiesand traced their density dependence. Turning to the meson-exchange picture of the nucleon interaction,in SR approach the exchange by strongly correlated quark systems (mesons) is expressed in terms ofweakly correlated quark systems (radiative corrections were included) with the same quantum numbers.

The approach proved itself to be a consistent tool for solving various problems of nuclear physics-see [3], where the work of several groups is reviewed. Among these problems are those which aredifficult or unaccessible for the standard methods. For example, the SR approach enabled to investigateinternal structure of the nucleon, providing some features of the EMC effect.We show that the nonlinearcontributions to the scalar condensate κ(ρ) are provided by the pion cloud. Its simplified inclusion signalson a possible saturation mechanism. The rigorous treatment leads to a self-consistent scenario. The pionpropagator, renormalized by the interactions in the matter depends on the nucleon effective mass m∗,and thus the condensate κ depends on m∗(ρ). On the other hand, the SR approach enables to calculatethe dependencem∗(κ). Hence, solution of the self-consistent equations provide the dependencies m∗(ρ)and κ(ρ). Inclusion of the hyperons enables to trace the phase transitions of the matter. Note that theapproach can be applied also for investigation of the systems with a finite density of strange baryons.

[1]. B. L. Ioffe, V. S. Fadin and L. N. Lipatov, Quantum Chromodynamics , Cambridge Univ. Press, 2010.[2]. E. G. Drukarev and E. M. Levin, Pis’ma ZhETF. 48, 307 (1988); (JETP Lett. 48, 338 (1988)).[3]. E. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova, Phys. Atom. Nucl. 75, 334 (2012).

HN 011


The role of two-nucleon mechanisms in pion photoproduction on nuclei in the region of

high momentum transfer.

M. Egorov, A. Fix 1 High mathematics and mathematical physics Departmen , NR Tomsk polytechnic University 634050, Tomsk,

Russia

Contact email: [email protected].

The contribution of two-nucleon mechanisms into quasi-free photoproduction of pions on p-shell nuclei is studied. In addition to the single-nucleon knockout A(γ,πN)B the channels with two free nucleons in the final state A(γ,πNN)B′ are considered. The simple spectator [1] model is shown to be unable to provide reliable description of the reaction in the kinematical region corresponding to high momentum transferrred to the residual nucleus [2]. Within this model the interaction between the final particles is ignored (or is taken into account as a mere absorption of the produced pions). As a result there is a strong mismatch between the large initial nucleon momentum needed to produce the pion in this region and the average available momentum in the target nucleus. Inclusion of interaction in the fianl state provides an efficient mechanism to compensate this momentum mismatch through the collision between the final particles. As a consequence inclusion of mechanisms where two nucleons are actively involved into reaction leads to a strong enhancement of the pion production rate in the high momentum transfer region. As the most important two-nucleon mechanisms appearing in the reaction A(γ,πNN)B′ we considered rescattering between the knocked-out nucleons, as well as pion rescattering and double pion photoproduction with the subsequent absorption of one of the pions on the second nucleon.

Figure 1: Differential cross section for quasifree pion photoproduction on 12

C. Data from Ref. [3].

The dotted, dashed and the solid lines correspond to the spectator model, inclusion of the final

particle absorption and to full calculation where two nucleon mechanisms are taken into account.

The dash-dotted line is obtained if only interaction between the knocked-out nucleons is added to the

spectator model.

Among the considered mechanisms, the role of NN interaction is shown to be the most significant (dash-dotted curve in Fig.1). Its inclusion provides sizable improvement of the model and leads to much better agreement with the existing data [3].

The work has been done with financial support of “Dynasty” foundation.

[1] R. Serber, Phys. Rev. 72, 1114 (1947); [2] I. Glavanakov et al., Sov. J. Nucl. Phys. 30, 465 (1979); Sov. Nucl. Phys. 49, 58 (1989); [3] I. Glavanakov et al., Phys. Atom. Nucl. 61, 2064 (1998);

HN 012

mailto:[email protected]


Spectroscopy of η′ Mesic Nuclei via Semi-Exclusive Measurement at FAIRH. Fujioka1, K. Itahashi2, S. Friedrich3, H. Geissel4, R. S. Hayano5, S. Hirenzaki6, S. Itoh5, D. Jido7,

V. Metag3, H. Nagahiro6, M. Nanova3, T. Nishi5, K. Okochi5, H. Outa2, K. Suzuki8, T. Suzuki5,Y. K. Tanaka5, and H. Weick4

1 Department of Physics, Kyoto University, Kyoto, 606-8502, Japan2 Nishina Center for Accelerator-Based Science, RIKEN, Saitama, 351-0198, Japan

3 II. Physikalisches Institut, Universitat Gießen, D-35392 Gießen, Germany4 GSI Helmholtzzentrum fur Schwerionenforschung GmbH, D-64291 Darmstadt, Germany

5 Department of Physics, The University of Tokyo, Tokyo, 113-0033, Japan6 Department of Physics, Nara Women’s University, Nara 630-8506, Japan

7 Department of Physics, Tokyo Metropolitan Univeristy, Tokyo, 192-0397, Japan8 Stefan-Meyer-Institut fur subatomare Physik, 1090 Vienna, Austria


The peculiarly large mass of an η′ meson is theoretically attributed to the interplay between chiralsymmetry breaking and axial anomaly [1]. Accordingly, at finite density, where chiral symmetry ispartially restored, the η′ mass may be reduced. For example, the Nambu–Jona-Lasinio model suggeststhat the mass reduction at the normal nuclear density amounts to 150MeV/c2 [2]. This indicates thatthe interaction between an η′ meson and a nucleus is attractive, and that an η′-nucleus bound state mayexist. While there is no experimental information on the strength of the interaction nor the existence ofthe bound state, a small absorption width of η′ at the normal nuclear density (15–25MeV) is reportedby CBELSA/TAPS [3]. The suggested narrow absorption width stimulates an experimental study of η′

mesic nuclei.As a first step, we plan to carry out a missing-mass spectroscopy experiment at GSI, by using the

(p,d) reaction on 12C target [4] in the near future. We will adopt an inclusive measurement, where wedetect the ejectile deuteron by the fragment separator FRS as a spectrometer. While the backgroundmainly from quasi-free multi-pion production processes (p+N → d+ π’s) dominates, the observationof an excited state η′ mesic nuclei near the η′ production threshold may be realistic, according to thetheoretical calculation [5] and the background evaluation.

As a possible extension, we are investigating a feasibility to carry out a semi-exclusive measurementwith an additional proton tagging from the decay of η′ mesic nuclei, such as η′N → πN , η′N → ηN ,η′NN → NN . Such a coincidence measurement will be enabled with the fragment separator SuperFRSat FAIR, which is under construction, since the region between the pre-separator and the main separatoris wide enough to install the proton-tagging counter as well as the carbon target. The counter will belocated at a a backward angle, in order to suppress the influence of the multi-pion production processesas much as possible.

In this contribution, the concept of the experiment with SuperFRS/FAIR, as well as the R&D statusof the proton-tagging counter system, will be discussed.

[1] D. Jido, H. Nagahiro, and S. Hirenzaki, Phys. Rev. C 85, 032201 (2012).[2] H. Nagahiro, M. Takizawa, and S. Hirenzaki, Phys. Rev. C 74, 045203 (2006).[3] M. Nanova et al., Phys. Lett. B 710, 600 (2012).[4] K. Itahashi et al., Letter of Intent for GSI-SIS (2011); K. Itahashi et al., Prog. Theor. Phys. 128, 601 (2012).[5] H. Nagahiro et al., arXiv:1211.2506 [nucl-th].

HN 013


Dynamics of multi-Λ hypernuclei in antiproton-induced reactions

T. Gaitanos1, A.B. Larionov2, H. Lenske1, U. Mosel1

1 Institut fur Theoretische Physik, Justus-Liebig-Universitat Giessen, D-35392 Giessen, Germany2 Frankfurt Inst. for Adv. Studies, J.W. Goethe-Universitat, Frankfurt, Germany


The knowledge of hyperon-nucleon and hyperon-hyperon interactions is essential for a deeper un-derstanding of baryonic matter as found, e.g., in nuclear astrophysics. Strangeness dynamics is still awidely debated theoretical and experimental topic of current research. Reactions induced by heavy-ionsand (anti)hadron beams on nuclear targets offer a promising opportunity to explore the still little knownstrangeness sector of the equation of state at ordinary nuclear densities and beyond. In such reactions,which will be experimentally studied at the forthcoming FAIR and J-PARC facilities, we investigatethe formation and propagation of strangeness particles with the associate production of multi-strangehypernuclei using a dynamical transport model (Giessen Boltzmann-Uehling- Uhlenbeck, GiBUU) [1]extended by a statistical approach (Statistical Multifragmentation Model, SMM) [2] of fragment for-mation. First theoretical predictions on a quantitative level on spectra and inclusive cross sections ofdouble-Λ hypernuclei have been already reported in Ref. [3]. Recently, in-medium dependences of theelementary hyperon-nucleon channels have been studied [4], by solving the in-medium Bethe-Salpeterequation. A strong density dependence of the hyperon-nucleon cross sections was found, particularly,at low energies. Note that for the formation of hypernuclei slow-moving hyperons are necessary [3]. Itis therefore of particular interest to study the in-medium effects, arising from the elementary channelsas well as from the hyperon-nucleon (and also kaon-nucleon) mean-fields, in reaction dynamics. In thiscontribution we discuss in detail these in-medium dependences on the production of strangeness andhypernuclei in reactions induced by antiproton beams.

[1] O. Buss,et. al, Phys. Rep.512 (2012) 1.[2] A.S. Botvinaet al., Nucl. Phys.A475 (1987) 663; J.P. Bondorfet al., Phys. Rep.257 (1995) 133.[3] T. Gaitanos,et. al, Nucl. Phys.A881 (2012) 240.[4] T. Gaitanos,et. al, Nucl. Phys. in press (2013),http : //dx.doi.org/10.1016/j.nuclphysa.2012.12.124.

HN 014


Neutron-rich hypernuclei beyond 6ΛH

A. Gal1, D.J. Millener2

1 Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel2 Physics Department, Brookhaven National Laboratory, Upton, NY 11973, USA


Recent experimental evidence presented by the FINUDA Collaboration for a particle-stable6ΛH [1]

has stirred renewed interest in charting the limits of particle-stable neutron-richΛ hypernuclei, partic-ularly when the nuclear core is unbound. Ongoing few-body calculations of6

ΛH have been reported inHYP2012 [2], and a(π−, K+) experiment on6Li and 9Be targets is underway at J-PARC [3].

We have studied theoretically within a shell-model approach several neutron-richΛ hypernuclei inthe nuclearp shell that may be formed in(π−, K+) or in (K−, π+) reactions on stable nuclear targets.The relevant hypernuclear shell-model matrix elements are taken from a theoretically-inspired successfulfit [4] of γ-ray transitions inp-shellΛ hypernuclei [5] which includes alsoΛN ↔ ΣN coupling. Predic-tions will be given for the binding energies of9

ΛHe,10ΛLi, 12ΛBe,14ΛB. None of the large effects conjectured

by Akaishi and Yamazaki [6] to arise fromΛN ↔ ΣN coupling is borne out by these detailed realisticshell-model calculations. This is evident from the relatively modestΛN ↔ ΣN component of the totalbeyond-mean-field contribution to theΛ hypernuclear g.s. binding-energy, marked∆B

g.s.Λ in Table 1. A

detailed exposition will be given during the presentation.

Table 1: Beyond mean field∆Bg.s.Λ shell-model contributions (in keV) to g.s. of neutron-rich hypernuclei

target n–rich less2n Λ − Σ Λ − Σ induced ∆Bg.s.Λ

AZ AΛ(Z − 2)

(A−2)Λ (Z − 2) last2n total lN · sN total

6Li 6ΛH(0+) 4

ΛH(0+) 101 101 176 2789Be 9

ΛHe(12+

) 7ΛHe(12

+) 152 253 619 879

10B 10ΛLi(1−) 8

ΛLi(1−) 115 275 595 102212C 12

ΛBe(0−) 10ΛBe(1−) 123 158 554 748

14N 14ΛB(1−) 12

ΛB(1−) 152 255 458 785

[1] M. Agnello et al. (FINUDA + A. Gal), Phys. Rev. Lett. 108 (2012) 042501, Nucl. Phys. A 881 (2012) 269.[2] B.F. Gibson, I.R. Afnan, to appearin the proceedings of HYP2012, Nucl. Phys. A (2013); E. Hiyama, toappear in the proceedings of HYP2012, Nucl. Phys. A (2013).[3] See http://j-parc.jp/researcher/Hadron/en/Proposale.html for J-PARC experiment E10.[4] D.J. Millener, Nucl. Phys. A 881 (2012) 298, and references therein.[5] H. Tamura et al., Nucl. Phys. A 835 (2010) 3, and references therein.[6] Y. Akaishi, T. Yamazaki, inPhysics and Detectors for DAΦNE, Eds. S. Bianco et al., Frascati Physics SeriesVol. XVI (INFN, Frascati, 1999) pp. 59-74.

HN 015


High-Resolution Hypernuclear Spectroscopy at JLab Hall A. Results and perspectives Franco Garibaldi (INFN Roma1), on behalf of the Jlab Hall A hypernuclear collaboration

Hypernuclear spectroscopy via electromagnetic induced reactions is a valuable and powerful way to study hypernuclei, hadronic systems with non-zero strangeness content, providing an alternative to the hadron induced reactions mainly studied so far. Electron-induced hypernuclear spectroscopy has been studied in Hall A at Je!erson Lab [1] on three nuclei, 12C, 16O, and 9Be with unprecedented resolution and with an improved particle identification system, using a RICH detector, in order to unambiguously identify kaons, thus allowing the measurement of high-quality, almost background-free, hypernuclear spectra. Two superconducting septum magnets were added to the existing apparatus in order to permit particle detection at very forward angle providing a reasonable counting rate. These studies have provided the first quantitative information on core-excited states in hypernuclei. In the case of oxygen, a waterfall target has been employed allowing for the simultaneous measurement of hypernuclear production on oxygen and of elementary kaon-Λ electro-production on protons: a crucial measurement to disentangle the contribution of the elementary reaction from the measured hypernuclear production cross section, yielding direct access to the nucleus-hypernucleus transition structure. A Λ binding energy value for 16

ΛN calibrated against the elementary (e, e′K+) reaction on hydrogen, has been obtained. Final results for 12C, 16O, 9Be will be presented [1-3]. Results of Hall C experiments will be presented in another talk in this Conference. Since it is essential for further theoretical study of hypernuclei to collect enough information about L production on nucleons and about excitation spectra of a wide variety of Λ hypernuclei, a continuation of the successful hypernuclear program at JLab is very desirable. For these reasons Hall A and Hall C Jefferson Lab hypernuclear collaborations decided to merge and propose a new layout for the 12 GeV Jefferson Lab era that has the advantages of both the experimental setups. In fact the new experimental design not only widens and deepens the physics range but also dramatically improves production yield and efficiency allowing to study both mass spectroscopy on a wide range of nuclei (from few body to 208Pb) and pion decay spectroscopy at the same time [4]. Figs.1, 2 show the results obtained for 12C and 16O. Fig. 3 shows the new layout. Fig.112

ΛB excitation-energy spectrum

Fig.216ΛN binding-energy

spectrum Fig 3 The new experimental layout

1. F. Garibaldi, S. Frullani, P. Markowitz and J. LeRose, spokespersons, JLab proposal forE94-107

2. M. Iodice et al., Phys. Rev. Lett. 99, 052501 (2007).3. F. Cusanno et al, Phys. Rev. let. 103, 202501 (2009).4. G.M. Uricuoli et al. High Resolution Spectroscopy of 9

ΛLi by Electroproduction (in preparation)

5. P. Bydžovski,, F. Cusanno, F. Garibaldi, J.J. LeRose, P. Markowitz, D.J. Millener, S.N.Nakamura, J. Reinhold, and L. Tang. Letter of Intent to JLAB PAC39 for Study with HighPrecision on Electro-production of Λ and Σ Hypernuclei in Full Mass Range

HN 016


π −4He interactions in the ∆ resonance energy region

I. Gnesi1,2 on behalf of PAINUC collaboration

1 Dipartimento di Fisica, Universita di Torino and INFN,Sezione di Torino, I–10125, Torino, Italy2 Centro Studi e Ricerche “E. Fermi”, Roma, Italy


PAINUC experiment obtained the first experimental evidence for the presence of a radiative interactionchannel inπ4He interaction:π±4He→ π±4Heγ. The main physical feature of the channel is the goodagreement of theγs energy distributions with the radiation distributions of a Planck blackbody at T∼16MeV. Besides, the first experimental observation of the excitation of the∆− resonance, below the thresh-old energy for pion production, has been obtained. The resonant invariant mass of theπ−n system hasbeen measured at Mπn =(1157± 14) MeV/c2 with a widthΓ =(38±2) MeV/c2, thus shifted with re-spect to the free nucleon∆ values. The resonance has been found to be formed at high three-momentumtransfer and at low Q2, suggesting that its excitation involves more than one nucleon.The positive pion absorption reaction (π+ 4He→ 3pn) in the∆ resonance energy region shows strongangular correlations and weak Final and Initial State Interactions (FSI/ISI) among final state nucleons,for all the different two-nucleons and three-nucleons systems. On the basis of model-independent kine-matical arguments the branching ratio of pion absorption on systems of three or four nucleons has beenevaluated to be∼14%; even if signatures of pd absorption are observed, where the slow proton is just aspectator, interesting signatures of pure 3-4 nucleon absorption are also present, supporting the hypothe-sis of the excitation of a nuclear collective resonance.

According to the experimental findings, the physical features of theπ induced collective resonancehave been extracted, according to a two parameters semi-empirical model, by fitting data from a collec-tion of resonantπA elastic scattering cross sections. The contributions to the total binding energy pereach additional nucleon has been found to be EB >50 MeV, being 7 times more than the binding energyper nucleon in4He; the interaction strength with the surrounding nuclear medium seems to steeply fallwithin a range of 1 fm [1].

The direct measurement of the muon neutrino mass is also being studied at PAINUC since the mostaccessible channel for its direct study is the pion decay. A high precision simulation has been performed,studying the limits onmν imposed byπ/µ momentum resolutions and masses. The required resolutionfor resolving a 1 keV/c2 neutrino is 1 meV/c: this value can be reached in a near future. The poorpion mass resolution, at present 350 eV, heavily constrains the accessiblemν sector above 419 keV/c2.Finally, from a set ofπ± decays, collected at PAINUC, new upper limits of the muon (anti)neutrinoshave been extracted.

[1] I. Gnesi et al., EPJA 47:3 (2011);

HN 017


A search for the K−pp bound state in the 3He(inflight-K−,n) reactionat J-PARC

T. Hashimoto for the J-PARC E15 Collaboration

Department of Physics, The University of Tokyo, Tokyo, 113-0033, Japan


Kaonic nuclei are extremely valuable systems to understand the KN interaction and the possible nuclearshrinkage caused by K meson. Especially, the simplest kaonic nuclear state,K−pp, is recently attractinggreat interest in both experimental and theoretical fields. Many theoretical calculations have been pro-gressed for theK−pp system, resulting in various binding energy and width predictions. Experimentally,however, only a small amount of information is available, which is not sufficient to discriminate betweena variety of conflicting interpretations.

In this situation, we are carrying out an experimental search of the K−pp bound state at J-PARCK1.8BR beam-line [1]. The most important key of our experiment is the inflight (K−,n) reaction at 1GeV/c. At this reaction, neutron backgrounds from non-mesonic two-nucleon absorptions or hyperondecays are expected to be substantially suppressed and kinematically separated. In addition, by usinga liquid 3He target and a large acceptance detector surrounding it, we can detect decay particles from“K−pp” to fully reconstruct the reaction kinematics. For this purpose, we have constructed a new spec-trometer system (fig. 1) [2], which has a quite unique feature of having large-acceptance high-resolutionneutron detector system in the forward direction. A cylindrical detector system (CDS) is also developedfor the detection of decay particles from the liquid 3He target.

A commissioning of the brand-new beam line and the spectrometer system has been completed.Figure 2 is a semi-inclusive (requiring 1 charged track in CDS) neutron 1/β spectrum of the 3He(K−,n) reaction obtained in the engineering run in June, 2012. The clear gap between the γ-ray peak and thebroad neutron distribution shows a well suppressed background. Both the missing-mass resolution of thisreaction and the invariant-mass resolution for the “K−pp” → Λp decay mode were revealed to be ∼10MeV/c2 as designed. Further engineering run with a forward proton detection system for the “K−pn”study was carried out in January, 2013. In the first-stage physics run planned in March, 2013, a neutronspectrum of more than 50 times statistics will be accumulated, which will enable us a coincidence studywith the decay particles detected in the CDS.

In this contribution, an overview of the experiment and a preliminary result of the first-stage physicsrun will be presented.

NeutronCounter

Trajectory of the neutron

Trajectory of the beam center

Beam sweepingmagnet CDS &target system Beam line

spectrometer

0 10 m

Figure 1: J-PARC K1.8BR spectrometer [2].

1 1.2 1.4 1.6 1.8 2 2.2 2.4

1

10

210

310

ƒÁneutron

Figure 2: Semi-inclusive neutron 1/β spectrum [2].

[1] M. Iwasaki et al., J-PARC E15 proposal, http://j-parc.jp/NuclPart/pac 0606/pdf/p15-Iwasaki.pdf.[2] K. Agari et al., [J-PARC E15 collaboration], Prog. Theor. Exp. Phys. (2012) 02B011.

HN 018


Structure of Be hyper isotopes

M. Isaka1, H. Homma1, M. Kimura1

1 Department of Physics, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan.


In this talk, we will discuss the low-lying structure of Be hyper isotopes by using Antisymmetrized Molecular Dynamics (AMD). One of the unique and interesting aspects of hypernuclei is the structure change caused by hyperon. Through the interaction with surrounding nucleons, a hyperon in the atomic nucleus can affect and modify nuclear clustering and deformation. Especially the structure changes of Be hyper-isotopes are of interest, since the Be isotopes have characteristic cluster structure with 2 clustering.

In the ground states of Be isotopes, it is well known that an clustering is affected by extra neutrons and the clustering and deformation are changed depending on the number of neutron. Indeed, such exotic structure appears as an abnormal parity of the ground state in 11Be [1]. The observed spin parity of the ground state is , while 11Be with the seven neutrons should have state as the ground state. By adding a hyperon to them, the drastic structure changes are expected because a hyperon can affect and modify the clustering and deformation of nuclei. In the other Be isotopes, the different kinds of structure changes are also expected by hyperon. For example, it is interesting to reveal the excitation spectra of 10

Be, because the resonance state of 9Be will be bound by the glue like role of hyperon and it will be observed by the JLab experiments.

To study such phenomena, we have applied an extended version of Antisymmetrized Molecular Dynamics for hypernuclei (HyperAMD [2]) to Be hyper isotopes. By using the YNG and Gogny D1S as the effective N and NN interactions, we have investigated the low-lying spectra and electro-magnetic transition rates of Be hyper-isotopes systematically without any assumption on the clustering. It is found that the abnormal parity of the 11Be ground state is reverted by hyperon and 12

Be has the normal shell order as shown in Figure 1. In this talk, we will discuss the changes of the clustering by hyperon and its effects to the excitation spectra for several Be hyper isotopes as well as 12

Be.

Figure 1: Calculated excitation spectra of 11

Be and 12

Be. [1] Y. Kanada-En'yo and H. Horiuchi, Phys. Rev. C 66, 024305 (2002); [2] M. Isaka, M. Kimura, A. Dote, and A. Ohnishi, Phys. Rev. C 83, 044323 (2011).

HN 019


Excited states with hyperon in p orbit in 25Mg

M. Isaka1, M. Kimura1, A. Dote2,3 and A. Ohnishi4

1 Department of Physics, Hokkaido University, Sapporo 060-0810, Japan 2 Institute of Particle and Nuclear Studies, KEK, Tsukuba, Ibaraki 305-0801, Japan

3J-PARC Branch, KEK Theory Center, IPNS, KEK, 203-1, Shirakata, Tokai, Ibaraki, 319-1106, Japan 4 Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502, Japan


In this talk, we will discuss the level structure of the excited states with a hyperon in p orbit in triaxially deformed hypernucleus 25

Mg by using the Antisymmetrized Molecular Dynamics (AMD). Forthcoming experiments at J-PARC will reveal the spectroscopy of sd-shell hypernuclei that have various kind of deformation. 24Mg is a largely deformed nucleus in sd-shell region and is one of the candidates for triaxially deformed nuclei, because of the existence of the K = 2+ side band build on the 2+

2 state at small excitation energy. In triaxially deformed nuclei, the response to the addition of a particle will be different

from those of axial symmetric nuclei [1]. Especially, the level structure of the excited states with the hyperon in p orbit will be quite different from that of the axially symmetric deformed nuclei such as 9

Be where the hyperon in p orbit will generate two kinds of p states [2, 3]. Since the p orbit of the hyperon in nuclei has anisotropy along with three directions, the binding energy of the hyperon in each p orbit is different from each other in triaxial deformed hypernuclei. Therefore, it is expected that the excited states with hyperon in p orbit will split into three states corresponding to the axis of deformation in triaxial deformed 25

Mg. To study such phenomena, we have applied an extended version of the AMD for hypernuclei (HyperAMD [4]) to 25

Mg. The AMD model is a microscopic model describing low-lying structure without any assumption on symmetry of nuclei. It is found that the hyperon in p orbit generates three different states in 25

Mg as shown in Figure 1. In this talk, we will show the excitation spectra of 25

Mg, and discuss the structure of these three states compared with the axial symmetric hypernucleus 9

Be.

Figure 1: Calculated excitation spectra of 25Mg with hyperon in p orbit.

[1] M. Isaka, et al., Phys. Rev. C 85, 034303 (2012); [2] R. H. Dalitz and A. Gal, Phys. Rev. Lett. 36 (1976) 362; [3] H. Bando, M. Seki, and Y. Shono., Prog. Theor. Phys. 66, 2118 (1981); [4] M. Isaka, M. Kimura, A. Dote, and A. Ohnishi, Phys. Rev. C 83, 044323 (2011)

HN 020


Feasibility Study of Pionic Atom Spectroscopy with Unstable NucleiK. Itahashi1, H. Fujioka2, R.S. Hayano3, T. Nishi3, K. Okochi3, Y.K. Tanaka3, Y.N. Watanabe3

1 RIKEN Nishina Center, RIKEN, Wako, 351-0198 Saitama, Japan2 Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-8052, Japan

3 Department of Physics, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan


We will present our most recent results in the feasibility study toward deeply bound pionic atom spec-troscopy with unstable nuclei [1]. We set our goal to an experiment in the RI beam factory (RIBF) ofRIKEN using an inverse-kinematics reactions d(HI, 3He), where HI denotes unstable nuclei, with a mod-erate spectral resolution of 700 keV (FWHM) and with a realistic data accumulation rate of > 103/dayat the first stage of the experiment. The assumed secondary beam intensity is 108/second.

Precision spectroscopy of deeply bound pionic atoms has been providing stringent constraints onthe physics of low energy region of QCD [2,3]. One of the most important achievements is the firstquantitative evaluation of the chiral condensate <qq>0.6ρ0 at the nuclear density of 0.6 ρ0 where ρ0

denotes the nuclear saturation density. Presently we are conducting a series of experiments at RIBF tomake a systematic high precision spectroscopy of pionic atoms with stable nuclei [4] aiming at unprece-dented resolution of < 300 keV (FWHM) in order to improve the <qq>0.6ρ0 precision by reducing theexperimental ambiguities.

Proceeding further to the spectroscopy of deeply bound pionic atoms with unstable nuclei, we have achance for the first time to achieve information on the density dependence of the chiral condensate, whichwill place an indispensable milestone for understanding the whole picture of spontaneous breaking ofchiral symmetry [5].

For the spectroscopy of pionic atoms with unstable nuclei, we need to employ reactions with a so-called inverse kinematics d(HI, 3He). We measure the Q value of the reaction to deduce the mass of thereaction products, pionic atoms. We need to detect emission angle and momentum of the recoil 3He withthe kinetic energy of about 60 MeV. This very low momentum requires delicate design of the experiment.The reaction vertices must be determined precisely otherwise the energy loss of the low-momentum 3Hewill deteriorate the spectral resolution miserably.

We have elaborately examined experimental feasibility in cases of solid, liquid, and gaseous targetsand came to conclude that the experimental feasibility will remain only in a deuterium gaseous target ina TPC (time projection chamber) used as an active target. A set of silicon detectors will be placed todetect the full energy of 3He.

Based on above considerations, we will present the detailed simulation results in terms of the spectralresolution and the yield of the pionic atom formation with unstable nuclei.

[1] K. Okochi et al., to be submitted to Nucl. Instr. Meth.[2] K. Itahashi et al., Phys. Rev. C62 , 025202 (2000).[3] K. Suzuki et al., Phys. Rev. Lett. 92, 072302 (2004).[4] T. Nishi et al., Accel. Prog. Rep. of RIKEN Nishina Center 45., iv (2012).[5] T. Hatsuda and T. Kunihiro, Phys. Rep. 247, 221 (1994), and references therein.

HN 021


RIKEN’s activity at J-PARC Hadron HallM. Iwasaki1

1 RIKEN Nishina Center, ILs, RIKEN, Hirosawa 2-1, Wako-shi, 351-0198, Japan


J-PARC has been founded to accommodate wide range of scientific fields utilizing high intensityproton accelerator research complex, as a joint project between KEK (High energy accelerator researchorganization) and JAEA (Japan atomic energy agency). One of the research objective of J-PARC is thefundamental physics using slow-extracted 30 GeV proton beam to the Hadron Hall bombarding on thefixed nuclear target, and delivering variety of secondary particles, such as π±, K±, K0 and p. Theintensity of the proton beam is ∼ 20 kW at present, and it is keep improving towards its design value offew 100 kW.

RIKEN’s research groups have been committed several research programs at K1.8BR kaon beam lineand High-p primary proton beam line of J-PARC Hadron Hall. In both cases, we are focused on the studyof meson property change in nuclear medium. The K1.8BR spectrometer system is equipped with largeneutron counter system in the forward angle. Using this unique feature, we are running E15 experimentfor deeply bound kaonic nuclear state search using 3He(K−, n) < K−pp > reaction, and preparing E31for the study of Λ(1405) using d(K−, n)Λ(1405) reaction. We are also preparing several experimentsusing p beam at K1.8BR by upgrading our experimental apparatus. At High-p line, we are preparingE16 for the study of in-medium mass shift of φ mesons in nuclei via the invariant-mass spectroscopy ofe+e−-pair using A(p, e+e−)X reaction. Very recently, the construction budget of High-p line had beenapproved, and will be constructed within two years. On the other hand, the size of the J-PARC HadronHall is still quite limited compared to the facility scale. Therefore, cooperating with KEK Hadron groupand Hadron Hall users association (HUA), we established our design proposal how to extend the HadronHall to fulfill next generation experimental programs as shown in the figure.

In this paper, we will describe some of the results of our present experiments, and overview theHadron Hall extension plan.

Figure 1: Schematic figure of the J-PARC Hadron Hall extension plan.

HN 022


Nonmesonic weak decay of light hypernuclei withinsoft ¼ +K meson-exchange model

Franjo Krmpotic1

1 Instituto de Fısica La Plata, CONICET, 1900 La Plata, Argentina, and Facultad de Ciencias Astronomicas yGeofısicas, Universidad Nacional de La Plata, 1900 La Plata, Argentina.


Studies of exotic nuclei, such as those possessing large isospin, or including hadrons with nonstandardflavor quantum numbers(strangeness, charm or bottom) are of continuous interest. Particularly inter-esting is the hypernucleus, that is formed when a hyperon, specifically a Λ-hyperon with strangenessS = −1, replaces one of the nucleons. Since this strange baryon is stable against strong and electromag-netic decays, and as it does not suffer from Pauli blocking by other nucleons it can live long enough inthe nuclear environment to become bound. The composed system acquires different properties from thatof the original one, such as the occurrence of the nonmesonic weak decay (NMWD): ΛN → nN withN = p, n, which is the main decay channel for medium and heavy hypernuclei. This process takes placeonly within nuclear environment, and is the unique opportunity that nature offers us to inquire aboutstrangeness-flipping baryon-baryon interaction.

Kinetic energy and coincidence spectra in NMWD of light hypernuclei have been evaluated in a sys-tematic way for the first time, adopting as theoretical framework the independent particle shell model andthree different one-meson-exchange transition potential. We have considered only one-nucleon inducedprocesses, neglecting entirely the events induced by two-nucleon emission, as well as the effects of thefinal state interactions. The comparison with data strongly suggests that the ¼ + K meson-exchangemodel with soft monopole form factors could be a good starting point for describing the dynamics re-sponsible for the decays of 4

ΛHe, and 5ΛHe hypernuclei. The importance of the recoil effect in defining

the shape of spectra in light hypernuclei is highlighted.

HN 023


Search for the η-mesic 4He with WASA-at-COSY

W. Krzemien1, P. Moskal1, 2, J. Smyrski1 and M. Skurzok1

for the WASA-at-COSY collaboration

1 M. Smoluchowski Institute ofPhysics, Jagiellonian University, 30-059 Cracow, POLAND2 IKP, Forschungszentrum Julich, D-52425 Julich, GERMANY


An exclusive measurement of the excitation function for thedd →3Hepπ− reaction was performed

at the Cooler Synchrotron COSY-Julich with the WASA-at-COSY detection system. The data weretaken during a slow acceleration of the beam from 2.185 GeV/c to 2.400 GeV/c crossing the kinematicthreshold for theη production in thedd →

4Heη reaction at 2.336 GeV/c. The corresponding excessenergy with respect to the4He− η system varied from -51.4 MeV to 22 MeV. No signal of the4He− η

bound state was observed in the excitation function. An upper limit for the cross-section for the boundstate formation and decay in the processdd → (4He− η)bound →

3Hepπ−, was determined on the 90% confidence level. In November 2010 a new data set was collected. The status of the research will bepresented.

HN 024


Manifestation of multibaryons in hadronic collisions at intermediateenergies

V.I. Kukulin, M.N. Platonova

Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991, Moscow, Russia


Although the exotic dibaryons, mainly with signatures I(JP ) = 0(3+) and 1(2+), in the form of six-quark bags have been predicted still long ago (see, e.g., [1]) and have been often used to explain differenthadronic phenomena accompanied with high momentum transfer and also the EMC effect, their experi-mental status has been rather unclear up to recent years. However in last few years the WASA-at-COSYcollaboration reported [2,3] about a quite reliable discovery of a dibaryonic resonance D∗ with a signa-ture I(JP ) = 0(3+), having the mass MD∗ ' 2.37 GeV and the total width ΓD∗ ' 70 MeV. It is veryimportant that the basic parameters of this isoscalar resonance and also the another, isovector dibaryonwith I(JP ) = 1(2+) (found in the phase-shift analyses of NN → NN , πd → πd and πd → NNprocesses) were in a full coincidence with those predicted by Dyson and Xuong [1] still in 1964. Thisagreement provides some additional confirmation for existence of such dibaryon resonances.

On the other hand, we developed [4] more than a decade ago a model for fundamental nuclear forceat intermediate and short distances, in which an intermediate dibaryon production plays a crucial rolein a consistent explanation of both strong intermediate-range attraction and short-range repulsion inthe NN system [4,5]. The above mechanism has very numerous implications in hadronic collisions,e.g., to explain the high yield of cumulative particles or to treat the production of subthreshold hadrons(mesons, antiprotons, etc.). It should be stressed that in all such treatments we employ the same di- andmultibaryon model which has been used to describe the fundamental nuclear force and fit the empiricalNN phase shifts [5].

The main focus in the present review talk is on the consistent treatment of cumulative and subthresh-old production phenomena at intermediate energies. In particular, we will show that the basic scaleparameter which governs the momentum distribution of the secondary high-momentum nucleons emit-ted in the backward hemisphere can be deduced straightforwardly from the NN -potential form factorwhich has been fitted to the NN scattering. Another nice consequence of the dibaryon model is a newquantitative interpretation of the ABC puzzle discovered more than 50 years ago and had no consis-tent theoretical explanation up to now (see the dedicated talk at this conference). There are many otherinteresting implications of the dibaryon concept for the basic nuclear force, like an enhanced dileptonemission in heavy-ion collisions at E ∼ 1 GeV/u [6]. In the talk we discuss some of these intriguingimplications and their experimental confirmations.

[1] F.J. Dyson and N.-H. Xuong, Phys. Rev. Lett. 13, 815 (1964).[2] M. Bashkanov et al., Phys. Rev. Lett. 102, 052301 (2009).[3] P. Adlarson et al., Phys. Rev. Lett. 106, 242302 (2011).[4] V.I. Kukulin, I.T. Obukhovsky, V.N. Pomerantsev, and A. Faessler, Phys. At. Nucl. 64, 1667 (2001); J. Phys.G 27, 1851 (2001).[5] V.I. Kukulin, I.T. Obukhovsky, V.N. Pomerantsev, and A. Faessler, Int. J. Mod. Phys. E 11, 1 (2002).[6] G. Agakishiev et al. (HADES Collaboration), Phys. Lett. B 690, 118 (2010).

HN 025


Spectroscopy of the Hadronic Atoms: K-N Strong Interaction Effects

A. S. Kvasikova1, T.A. Florko

1 and D.E. Sukharev

1

1 Odessa State University - OSENU, P.O. Box 24a,65009, Odessa-9, Ukraine


Ab initio approach to description of the kaonic atoms spectra with précised accounting for

the relativistic, radiative, nuclear, strong kaon-nucleon interaction effects on the basis of the Klein-

Gordon-Fock equation and relativistic QED perturbation theory [1] is presented. For low orbits there

are the important effects due to the strong K-N interaction. The energy shift is connected with a

length of the hadron-nuclear scattering. It is carried out calculating energy parameters of X-ray

transitions group in the kaonic atoms of hydrogen, helium, W, Pb U and other, including estimating

the values of strong kaon-nuclear interaction energy levels shifts and widths, defining corrections

due to an electron screening, vacuum polarization etc to transition energies. The potential includes

SCF ab initio potential, the electric and polarization potentials of a nucleus (the Gauss models for a

nuclear charge distribution) [1]. The Lamb shift polarization part is treated in the Uhling-Serber

approximation and the self-energy part – within the Green function method.

The calculated X-ray spectrum for kaonic He and estimate of 2p level shift due to the strong

K-N interaction 1.57 eV are in the reasonable agreement with experimental data (cited shift 1.9eV)

by Okada et al (2008; E570; КЕК 12GeV, RIKEN Nishina Centre, JAPAN) and differ (about order)

of other experimental data by Wiegand-Pehl (1971), Batty et al (1979), Baird et al (1983) [2]. There

are also presented data on the shifts and widths of low-lying + Rydberg transitions in some heavy

kaonic atoms. As example, in table 1 we present our data on the energy shifts, induced by strong K-

N interaction in the kaonic atoms: W, Pb,U. The comparsion with avalable experimental and

alternative theoretical results is carried out.

Table 1: Calculated (C) and measured (M) shifts ∆E (keV), induced by strong K-N interaction:

a – theory Batty etal; b – our theory (data from [1,2] and refs, therein)

Reference M C-a C-b

W, 8-7 0.079 0.052 -0.003 0.038

W, 7-6 -0.353 -0.250

-0.967 -0.294

Pb, 8-7 0.072

0.047

-0.023 0.046

U, 8-7 0.12 0.032

-0.405 -0.213

-0.189 -0.205

[1] A. Glushkov, O. Khetselius, L. Lovett et al, Frontiers in Quant. Syst. in Chem.and Phys., ed.

Wilson S.,Grout P.,Maruani J. etal (Springer) 18, 541 (2008); Adv.in Theory of Atom. and Mol.

Syst., ed.Piecuch P., Maruani J.,Delgado-Barrio G. etal (Springer) 20, 125 (2009).

[2] C.Batty, M. Eckhause, K. Gall et al., Phys. Rev. C 40, 2154 (1989); J. Santos, F. Parente, S.

Boucard et al., Phys.Rev.A 71, 032501 (2005).

[3] S. Okada, G. Beer, H. Bhang, et al., Phys.Lett.B 653, 387 (2007); Nucl. Phys. A 790, 663

(2007).

[4] T. Ito et al., Phys. Rev. C 58, 2366 (1998); T. Ishiwatari & Siddharta Collab. Nucl. Instr. and

Methods in Phys. A 581, 326 (2007); Z. Zmescal on behalf of DEAR Collob., Proc. ICNP -Geteborg

(Sweden) P.W31 (2004).

HN 026

Hypernucleus production in heavy ion collision - a theoretical analysis

A. LeFevre1 , Y. Leifels1, C. Hartnack2 J.Aichelin2

1Gesellschaft fur Schwerionenforschung Darmstadt, Postfach 11 05 52, D-64220 Darmstadt,Germany 2SUBATECH,University of Nantes - IN2P3/CNRS - Ecole des Mines de Nantes ,4

rue Alfred Kastler, F-44072 Nantes Cedex 03, France

Contact e-mail: [email protected]

Hyper nuclei are not only a laboratory to study the interaction among strange and non strangebaryons [1] but can be as well a very useful tool to study the space time evolution of heavyion reactions . Therefore recently the first attempts have been made to produce hypernucleiin heavy ion reactions[2, 3]. If this method could be established not only hypernuclei can beproduced in numbers but their multiplicity and momentum space distribution provides alsovaluable information on the time evolution of heavy ion reactions. The reason is that the Λwhich is formed in these collisions has to find fellow nucleons to form a hyper nucleus andtherefore the production yield depends on the phase space distribution ( and not only themomentum distribution) of the nucleons around the Λ. As for normal multifragmentation [4]there will be two formation processes. Hypernuclei can be formed by coalescence type processesfrom participant matter. This will be the dominant process at midrapidity and will create lighthypernuclei. Around projectile and target rapidity for hyper nucleus formation the Λ has to beabsorbed in the preformed target/projecile fragments [4]. There also heavier hypernuclei maybe created. Because the Λ is produced by participant nucleons the hypernucleus production inthe target/projectile region will provide information about the interaction between spectatorsand participants and therefore about the space time evolution of the system. Such a space timeinformation is necessary to clarify the mechanism of multi fragmentation at these energies, whichis still not understood.

To study hyper nuclei we use for the time evolution of the heavy ion reaction the QuantumMolecular Dynamics program which propagates nucleons from the initial separation of projectiland target to the particles which are observed in the detectors. To identify fragments andespecially hyper nuclei we have improved our standard approach, SACA [5] , based on theSimulated Annealing (SACA) procedure which has successfully described fragment formationand even details like the bimodality of the fragment production from 50 AMeV up to 1 AGeV[6]. These improvement include the use of the Λ-N interaction, of quantum corrections and thesymmetry energy for the identification of hypernuclei.

We present the model in detail, show first comparisons with the recently measured hypernuclei at GSI and draw conclusions about the production mechanism.

[1] J. Pochodzalla, Acta Phys. Polon. B 42 (2011) 833 [arXiv:1101.2790 [nucl-ex]].

[2] T. R. Saito, D. Nakajima, C. Rappold, S. Bianchin, O. Borodina, V. Bozkurt, B. Gokuzumand M. Kavatsyuk et al., Nucl. Phys. A 881 (2012) 218.

[3] Private communication, FOPI collaboration

HN 027


Hadronization in Nuclei – Recent Multidimensional Results fromHERMES

Inti Lehmann1,2, for the HERMES collaboration

1 FAIR, Planckstr. 1, 64291 Darmstadt, Germany2 University of Glasgow, Glasgow, G12 8QQ, Scotland/UK


A method to investigate the process of quark fragmentation and hadronization is to measure hadron yieldswhen scattering off nuclei of various sizes. As the path length of hadronization is comparable to the sizeof a nucleus one can study the length/time dependence of hadronization. This is because hadron yieldsdepend on whether hadronization occurs inside or outside nuclear matter.

Hadron multiplicities in semi-inclusive deep-inelastic scattering were measured on neon, kryptonand xenon targets relative to deuterium at an electron-beam energy of 27.6 GeV at HERMES. Theseratios were determined as a function of the virtual-photon energy ν, its virtuality Q2, the fractionalhadron energy z and the transverse hadron momentum pt with respect to the virtual-photon direction [1].Recently, dependences were analysed separately for positively and negatively charged pions and kaonsas well as protons and antiprotons in a two-dimensional representation [2]. The latter results will help toconstrain mechanisms and models of hadronization much more decisively than by the use of integratedresults as traditionally done.

A few features particular to the two-dimensional representation will be highlighted in this contribu-tion. For example, at lower values of ν positive kaons do not show the typical rise of the multiplicityratio with ν when z > 0.4. In addition, protons were found to behave very differently from the otherhadrons.

[1] A. Airapetian et al., Nucl. Phys. B780 (2007) 1-27;[2] A. Airapetian et al., Eur. Phys. J. A47 (2011) 113.

HN 028


Antiproton-Nucleus Interactions and Meson Production on Complex

Nuclei

H. Lenske1, S. Lourenço1, S. Wycech1,2

1 Institut für Theoretische Physik, U. Gießen, D-35392 Gießen, Germany

2 National Center for Nuclear Studies, Hoza 69, 00-681, Warsaw, Poland

Contact email: horst.lenskephysik.uni-giessen.de.

Interactions of antiprotons with nuclei and the coherent production of mesons in antiproton annihilation on a nucleus are investigated in a fully microscopic approach. Initial and final state interactions are accounted for by newly derived optical potentials. Interactions of antiprotons are described by a meson and baryon exchange model, accounting for the strong coupling to the annihilation channels [1,2]. Meson-nucleus interactions over large ranges of incident energies are obtained by including high-lying resonances, much beyond the level followed by previous approaches. State-of-the-art HFB nuclear structure input is used for nuclear density distributions [3]. A fully quantum mechanical description of the reaction process is obtained on the basis of an extended eikonal approach. Elastic scattering in the initial antiproton and final meson-nucleus channels is well reproduced as far as data are available. The production vertex contains contributions from t- and u-channel baryon exchange processes and s-channel production by NN annihilation into intermediate resonances. The same types of diagrams are contributing to the dispersive parts of the antinucleon-nucleon and antinucleon-nucleus optical potentials. Results of exploratory studies on differential mass distributions and total cross sections for pion and kaon production in antiproton-nucleus annihilation reactions are presented. We pay special attention on the energy region to be investigates by PANDA@FAIR.

Figure 1: Pion-nucleon total cross sections (left) and angular distributions for two-pion production

on a Ni-isotope at Tlab=800 MeV. [1] S. Lourenço et al., Hyperfine Interactions 209, (2012) 117 [2] S. Lourenço et al. Genshikaku Kenkyu Suppl. (2013) in print. [3] H. Lenske, P. Kienle. Physics Letters B 647 (2007) 82

HN 029


Shape evolution of Ne isotopes and Ne hypernuclei: The interplay ofpairing and tensor interactions

A. Li1, E. Hiyama2, X.-R. Zhou1, H.Sagawa2,3

1 Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen361005, China

2 RIKEN Nishina Center, RIKEN, Wako 351-0198, Japan3 Center for Mathematics and Physics, University of Aizu, Aizu-Wakamatsu, Fukushima 965-8560, Japan


We study tensor and pairing effects on the quadruple deformation of neon isotopes based on a de-formed Skyrme-Hartree-Fock model with BCS approximation for the pairing channel. We extend theSkyrme-Hartree-Fock formalism for the description of single- and double-lambda hypernuclei adoptingtwo different hyperon-nucleon interactions. It is found that the interplay of pairing and tensor interac-tions is crucial to derive the deformations in several neon isotopes. Especially, the shapes of 26,30Ne arestudied in details in comparisons with experimentally observed shapes. Furthermore the deformations ofthe hypernuclei are compared with the corresponding neon isotopic cores in the presence of tensor force.We find the same shapes with somewhat smaller deformations for single Λ-hypernuclei compared withtheir core deformations. It is also pointed out that the latest version of hyperon interaction, the ESC08bmodel, having a deeper Λ potential makes smaller deformations for hypernuclei than those of anotherNSC97f model.

[1] A. Li, E. Hiyama, X.-R. Zhou, H. Sagawa, Phys. Rev. C, in press.

HN 030


First measurement of low momentum dielectrons radiated off cold nuclearmatter.

M.Lorenz 1 for the HADES collaboration

1 Goethe Universitat Frankfurt, Germany


The High Acceptance DiElectron Spectrometer HADES is installed at the Helmholtzzentrum furSchwerionenforschung (GSI) accelerator facility in Darmstadt. It investigates dielectron emission andstrangeness production in the 1-3 AGeV regime. A recent experiment series focusses on medium-modifications of light vector mesons in cold nuclear matter. In two runs, p+p and p+Nb reactions wereinvestigated at 3.5 GeV beam energy; about 9 · 109 events have been registered. In contrast to other ex-periments the high acceptance of the HADES allows for a detailed analysis of electron pairs with a lowmomenta relative to nuclear matter, where modifications of the spectral functions of vector mesons arepredicted to be most prominent. Comparing these low momentum electron pairs to the reference mea-surement in the elementary p+p reaction, we find in fact a strong modification of the spectral distributionin the whole vector meson region and will discuss these results [1].

[1] G. Agakishiev et al. [HADES Collaboration], Phys. Lett. B 715, 304 (2012);

HN 031


Charmonium photoproduction in coherent and incoherent heavy ion

collisions at the LHC

M.V.T. Machado1

1 Instituto de Física, Universidade Federal do Rio Grande do Sul, CEP 91501-970, Porto Alegre, Brazil


In this contribution we report the predictions for the photoproduction of the vector mesons Psi(1S)

and Psi(2S) in both coherent and incoherent ultrarelativistic heavy ion collisions collisions at the

Large Hadron Collider energies using the color dipole approach and the Color Glass Condensate

(CGC) formalism. In particular, we present our predictions for the first run of the LHC for PbPb

collisions at 2.76 TeV concerning the rapidity dependence distributions at forward and backward

regions. These results are presented in figure below including the coherent and incoherent

contributions and compare them to the ALICE experiment. Predictions are done for the Psi(2S)

photoproduction, which has not been properly addressed in literature and can be measured in the

current LHC experiments.

HN 032


Measurements ofthe 2H(p, n) breakup reaction at 170MeV for the studyof the three-nucleon force effects

Y. Maeda1, T. Saito1, H. Miyasako1, T. Uesaka2, S. Ota3, S. Kawase3, T. Kikuchi3, H. Tokieda3, T.Kawabata4, K. Yako3, T. Wakasa6, S. Sakaguchi6, R. Chen2, H. Sakaguchi7, T. Shima7, T. Suzuki7, A.

Tamii7

1 Department of Applied Physics, University of Miyazaki, 1-1 Gakuenkibanadai-Nishi, Miyazaki 889-2192, Japan2 RIKEN Nishina Center, Wako, Saitama 351-0198, Japan

3 CNS, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan4 Department of Physics, Kyoto University, Kyoto 606-8501, Japan

5 Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan6 Department of Physics, Kyushu University, Higashi-ku, Fukuoka 812-8581, Japan

7 RCNP, Osaka University, Ibaraki, Osaka 567-0047, Japan


Recently the effects of three-nucleon force (3NF) are regarded as important not only in the few-bodynuclear physics but also in the study of the nuclear structure or the astrophysics. Precise study of 3NFhas been actively performed by using the nucleon-deuteron (Nd) scattering states. The differential crosssections of the elasticNd scattering at the energy below 150 MeV can be well reproduced by adding3NF in the Faddeev calculation based on modern nucleon-nucleon (NN ) interactions [1-2]. On the otherhand, the differential cross sections ofNd elastic and inelastic scatterings at 250 MeV show large dis-crepancies between the data and the Faddeev calculations with 3NF [3-4], which indicates the presenceof the missing features of the three nucleon system at this energy region. And this large discrepancybetween the data and the theory was also shown in the2H(p, p)pn inclusive breakup reaction atEp =250 MeV [5]. For the systematic study about the energy dependence of this large discrepancies, we mea-sured the differential cross sections and the vector analyzing power Ay for the2H(p, n) inclusive breakupreaction at 170 MeV.

The experiment was carried out at RCNP. The polarized proton beam of 170MeV was injected to thedeuterated polyethylene (CD2) target and scattered neutrons were detected by using the neutron detectorNPOL3. The energy of a detected neutron was deduce by TOF method.

The data was compared with the results of the Faddeev calculations with and without the 3NF [6-7].Concerning about the differential cross sections, we can see large discrepancies between the data and thecalculations in the low neutron energy regions, which is similar to the results of the2H(p, p) inclusivebreakup reaction at 250 MeV.

[1] H. Sakai et al., Phys. Rev. Lett. 84, 5288 (2000);[2] K. Sekiguchi et al., Phys. Rev. C 65, 034003 (2002);[3] Y. Maeda et al., Phys. Rev. C 76, 014004 (2007);[4] K. Hatanaka et al., Phys. Rev. C 66, 044002 (2002);[5] S. Kuroita et al., AIP Conf. Proc. 1011, 98 (2008);[6] H. Witała, private communication.[7] A. Deltuva, private communication.

HN 033


Calculations of K nuclear quasi-bound states using chiral KN amplitudesJ. Mares1, N. Barnea2, A. Cieply1, E. Friedman2, A. Gal2, D. Gazda1

1 Nuclear Physics Institute, 250 68 Rez, Czech Republic2 Racah Institute of Physics, The Hebrew University, 91904 Jerusalem, Israel


We review our latest calculations of K− quasi-bound states in few- and many-body nuclear systemsusing subthreshold energy dependent chiral KN amplitudes [1,2].

We performed calculations of three-body KNN and four-body KNNN and KKNN nuclear clus-ters in the hyperspherical basis, with interactions practically identical to those used in ref. [3]. Resultsof previous K−pp calculations were reproduced and and upper bound was placed on the binding energyof a K−d quasibound state. In view of the low K−pp binding energy B(K−pp) ≈ 16 MeV and rela-tively large KN → πY mesonic width Γ(K−pp) ≈ 40 MeV, it might be difficult to identify the K−ppquasi-bound state unambiguously in ongoing experiments. A self-consistent handling of the energy de-pendence of the subthreshold KN amplitude was found to restrain binding of the four-body K nuclearclusters. We found relatively modest binding, about 30 MeV in both, with mesonic widths ranging from30 MeV for KNNN to about 80 MeV for the lowest KKNN quasi-bound state. However, the bind-ing energies of K− nuclear clusters could be enhanced by dispersive contributions. Our recent fits tokaonic atoms [4,5] suggest that ∆Bdisp ∼ ∆Γnonmesonic, and the binding energies could reach valuesB(K−pp) ∼ 25 MeV and B(KNNN, KKNN) ∼ 50 MeV.

For many-body K− nuclear systems with densities close to nuclear matter density, the energy de-pendence of the chiral in-medium KN scattering amplitudes controls the self-consistent evaluation ofthe corresponding K− optical potentials. We considered two in-medium versions of the scattering am-plitudes: a version which takes into account only Pauli blocking in the intermediate states, and a versionwhich adds self-consistently hadron self-energies [2,4]. The KN amplitudes were constructed usingthe in-medium coupled-channel model [6] that reproduces all available low energy KN observables, in-cluding the latest 1s level shift and width in the K− hydrogen atom from the SIDDHARTA experiment[7]. While the two in-medium versions of the KN scattering amplitudes yield considerably differentpotential depths ReVK at threshold, they give similar depths in the self-consistent calculations with thesubthreshold extrapolation, -ReVK ∼ 80 − 120 MeV. The mesonic widths of low-lying K− states aresubstantially reduced in the self-consistent calculations, thus reflecting the proximity of the πΣ threshold.On the contrary, the widths of higher excited K− states are quite large even if only the pion conversionmodes on a single nucleon are considered. After including 2 body K−NN → Y N nonmesonic modes,the total decay widths ΓK are comparable or even larger than the corresponding binding energies BK forall K− nuclear quasi-bound states, exceeding considerably the level spacing. Our conclusions shoulddiscourage attempts to search for isolated peaks corresponding to K− nuclear quasi-bound states inmany-body nuclear systems.

[1] N. Barnea, A. Gal, E. Z. Liverts, Phys. Lett. B 712 (2012) 132.[2] D. Gazda, J. Mares, Nucl. Phys. A 881 (2012) 159; Nucl. Phys. A in press.[3] A. Dote, T. Hyodo, W. Weise, Nucl. Phys. A 804 (2008) 197; Phys. Rev. C 79 (2009) 014003.[4] A. Cieply, E. Friedman, A. Gal, D. Gazda, J. Mares, Phys. Lett. B 702 (2011) 402;

Phys. Rev. C 84 (2011) 045206.[5] E. Friedman, A. Gal, Nucl. Phys. A 881 (2012) 150; Nucl. Phys. A 899 (2013) 60.[6] A. Cieply, J. Smejkal, Nucl. Phys. A 881 (2012) 115.[7] M. Bazzi et al. (SIDDHARTA Collaboration), Phys. Lett. B 704 (2011) 113; Nucl. Phys. A 881 (2012) 88.

HN 034


Microscopic Investigation of the Structure Characteristics and

Wave functions of the Five-Body Hypernucleus H 5

λ

Lia Leon Margolin

Department of Mathematics, Marymount Manhattan College, 221 East 71 street, New York, NY, USA


Parentage Scheme of Summarization to the N-body symmetrized basis construction [1] necessary

for the description of the structural characteristics and decay reactions of the hypernuclear and

nuclear systems with arbitrary amount of particles is applied to solve five-body problem in

hypernuclear physics. Five particle hypernucleus 5

λH as a system of four nucleons and one hyperon

is investigated with the use of the Hyperspherical Function Method in the momentum representation.

The dependence of the structure characteristics and wave functions on the types of nucleon-nucleon

ad hyperon-nucleon interaction potentials is studied. Mean Square λα − distance and binding

energies are obtained.

[1] L.Margolin., J. Phys. 343 (2012). doi:10.1088/1742-6596/343/1/012071

HN 035


J-PARC Experiment (E07) to Study Double Hypernuclei

K. Nakazawa1 on behalf of the J-PARC E07 collaboration2

1 Pysics Department, Gifu University, Gifu 501-1193, Gifu, Japan 2 Aligarh Muslim University, ASRC(JAEA), BNL, CIAE, Dongshin University, Fukui University,

Gyoengsang National University, IPNS(KEK), Kyoto University, Nagoya University, Pusan National University, RCNP(Osaka University), Seoul National University,

Shanxi Normal University, Toho University, Tohoku University, University Colledge of London, University of Huston


Double-Λ hypernuclei give us information about the Λ-Λ interaction which is valuable for unified understanding of Baryon-Baryon interaction in SU(3)-flavor symmetry. Nuclear physics with double strangeness also guides us to multi-strangeness systems such as “strange matter” and is closely related to the H-dibaryon. However experimental knowledge is very limited so far.

In the previous experiment E373 at KEK, we have succeeded to detect nearly one thousand events with Ξ- hyperon capture at rest in nuclear emulsion, where Ξ- hyperons were produced via quasi-free ‘p’(K-, K+)Ξ- reaction on diamond target. Among them, production and decay topology of double- Λ hypernucleus has been shown in 7 events. As for uniquely identified Nagara event (ΛΛ

6He), although it was published in PRL [1], the binding energy (BΛΛ) and the interaction energy (ΔBΛΛ) of two Lambda hyperons should be revised due to the change of the mass of Ξ- hyperon by 0.4 MeV in Particle Data (2008). The modified BΛΛ and the ΔBΛΛ using a new knowlege of Nagara event are summarised in elsewhere[2] with other three events of Mikage, Demachi-yanagi and Hida event under the check of the consistency of the ΔBΛΛ with that of Nagara event.

The comming experiment, E07 at J-PARC, is expected to give us about 102 and 103 double-Λ hypernuclei with a “new hybrid method” and “overall scanning method”, respectively. We probably succeed to detect nuclear species with two Λ hyperons other than Nagara event by such amount of double-Λ hypernuclear events.

As for “new hybrid method”, we have developed a system for full-automated track following by the success of precise position alignment (~1 μm) for emulsion plate by plate which size is 35 x 35 cm2. By using Ge-detector set around the emulsion, we will mesure X-ray of level energy for Ξ- hyperon capture in Ξ atom without any ambiguity, because the capture event are located in the emulsion. In “overall scanning” of the emulsion, we will search for double-Λ hyper nuclear events independent on the information by electrical detectors (counters, chambers and so on). It is expected that non-tagged event for Ξ- hyperon capture can be in the emulsion about ten or more times than that followed with the above “new hybrid method” due to limited acceptane of electric detectors. To carry out “overall scanning” in a few years, we develp very fast scanning system with CMOS Camera (800 Hz) and new lens barrel (piezo actuator). The system gives us ~ 200 times’ faster speed than that of the previous E373 experiment.

Although the beam expeosure for the E07 experiments, above introduced systems will start to work on the E373 emulsion from this march, then some new events of double-Λ hypernuclei can be detected in the coming spring. In our contribution, we will discuss physics given by the E07 experiment with developed apparatues, first, and report production of double-Λ hypernuclei, if it is possible. [1] H. Takahashi et al., Phys. Rev. Lett. 87, 212502 (2001); [2] K. Nakazawa and H. Takahashi, Prog. Theor. Phys. Suppl. 185, 335 (2010).

HN 036

Determination of the η′-nucleus optical potential?

Mariana Nanova

University of Giessen, Germany

Experimental approaches for determination of the η ′-nucleus potential arepresented. As discussed in [1] the transparency ratio measurements pro-vide information on the inelastic cross section and in-medium width of η ′

and thereby on the imaginary part of the η ′-nucleus potential. The rela-tively narrow in-medium width of about 20 MeV of the η ′-meson makes it apromising candidate for a mesic state only bound by the strong interaction[2]. Therefore, it is very important to learn more about the real part of theη′-nucleus optical potential. The momentum distribution and the excitationfunction show some sensitivity to in-medium modifications and could pro-vide information on the sign and depth of the potential. Data taken in 2009at CB/TAPS@ELSA on a carbon target have been analysed and comparedto model calculations [3] assuming different scenarios for the real part ofthe potential, related directly to the in-medium mass modification of themeson. The preliminary results are consistent with an only weakly attrac-tive η′-nucleus potential and do not favour theoretical predictions claimingpotential depth of -100 to -200 MeV.[1] M. Nanova et al., Phys. Lett. B 710 (2012) 600[2] H. Nagahiro et al., Phys. Lett. B 709 (2012) 87[3] E. Paryev, J. Phys. G: Nucl. Part Phys. 40 (2013) 025201.

?Funded by DFG(SFB/TR-16)

1

HN 037


The first precision measurement of deeply bound pionic states in 121SnT. Nishi 1, G.P.A. Berg2, M. Dozono3, H. Fujioka4, N. Fukuda3, T. Furuno4, H. Geissel5,

R.S. Hayano1, N. Inabe3, K. Itahashi3, S. Itoh1, D. Kameda3, T. Kubo3, H. Matsubara3, S. Michimasa7,K. Miki6, H. Miya7, Y. Murakami1, M. Nakamura3, N. Nakatsuka4, S. Noji1, K. Okochi1, S. Ota7,

H. Suzuki3, K. Suzuki8, M. Takaki7, H. Takeda3, Y.K. Tanaka1, K. Todoroki1, K. Tsukada9,T. Uesaka3, Y.N. Watanabe1, H. Weick5, H. Yamada1, and K. Yoshida3

1 Department of Physics, University of Tokyo, Tokyo, 113-0033, Japan2 JINA and Department of Physics, University of Notre Dame, Indiana, 46556, USA3 Nishina Center for Accelerator-Based Science, RIKEN, Saitama, 351-0198, Japan

4 Department of Physics, Kyoto University, Kyoto, 606-8502, Japan5 GSI Helmholtzzentrum fur Schwerionenforschung GmbH, D-64291 Darmstadt, Germany

6 Research Center for Nuclear Physics, Osaka University, 567-0047 Osaka, Japan7 Center of Nuclear Study, University of Tokyo, Tokyo, 113-0033, Japan

8 Stefan Meyer Institut fur subatomare Physik, 1090, Vienna, Austria9 Department of Physics, Tohoku University, 980-8578, Sendai, Japan


We report our recent experiment of the pionic 121Sn atom using missing-mass spectroscopy of the122Sn(d,3He) reaction near the － emission threshold. While a detailed analysis is on-going, preliminaryspectra already show distinct structures in bound region. The experiment serves as a pilot experiment forsystematic study of deeply bound pionic atoms at the RIKEN RI beam factory (RIBF).

Recent studies revealed that the chiral condensate at the normal nuclear density can be deduced byprecision spectroscopy of pions captured in deep states (such as 1s or 2p) of heavy atoms, which arecalled deeply bound ponic atoms[1, 2]. So far the 1s pionic states in 205Pb and 115,119,123Sn have beendiscovered at GSI [3-5]. The deduced chiral order parameter was compared with that of the vacuum,which was deduced from the pionic hydrogen, and partial chiral restoration was suggested. However, theevaluation still had large systematic and statistical errors. To reduce the systematic errors from ambiguityof the nuclei, we are planning the pionic Atom Factory (piAF) project, in which the deeply bound pionicatoms of isotopes and isotones will be produced.

As a pilot experiment for the project, we performed a precision spectroscopy of the 122Sn(d,3He)reaction. In the experiment, we succeeded in the first observation of the pionic states in 1s and someother orbits of 121Sn and the angular dependence of the pionic-atom formation cross section owing to thelarge angular acceptance of the BigRIPS spectrometer [6]. The resolution was at least as good as in theprevious experiment. At the same time, the data-taking time was reduced dramatically, which is essentialfor the systematic spectroscopy. These results revealed the encouraging potential capability of the RIBFfacility for systematic high-precision spectroscopy of deeply-bound pionic atoms.

Now we are working to decompose the spectrum to each state and extract the chiral order parameter.The current status of the analysis, including new results about the angular dependence of the pionic-atomformation cross section for each state, will be reported.

[1]E. E. Kolomeitsev, N. Kaiser, and W. Weise, Phys. Rev. Lett. 90, 092501 (2003).[2]D. Jido, T. Hatsuda and T. Kunihiro, Phys. Lett. B 670, 109 (2008).[3]K. Itahashi et al. , Phys. Rev. C 62, 025202 (2000).[4]H. Geissel et al. , Phys. Rev. Lett. 88, 122301 (2002).[5]K. Suzuki et al. , Phys. Rev. Lett. 92, 072302 (2004).[6]T. Nishi et al. , Accel. Prog. Rep. of RIKEN Nishina Center 45, iv (2012).

HN 038


New interpretation of the ABC effect in the basic double-pionic fusionreaction

M.N. Platonova, V.I. Kukulin

Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, 119991, Moscow, Russia


The ABC effect first observed by Abashian, Booth and Crowe [1] more than 50 years ago stands for apronounced near-threshold enhancement in the ππ invariant mass spectrum of the double-pionic fusionreactions, such as pn → d + ππ, pd → 3He + ππ, etc. Numerous theoretical and experimental studiesundertaken since the discovery of the ABC effect shed light on its basic features, such as its scalar-isoscalar nature. However the effect has not received a reliable and commonly accepted theoreticalexplanation up to now.

The interest in the ABC effect has increased again quite recently, after publication of the results of thefirst exclusive and kinematically complete experiments for the basic 2π-fusion reaction pn → d + π0π0

in the ABC region (Tp = 1.0–1.4 GeV) done by WASA-at-COSY collaboration [2]. The comparisonof the new experimental data with theoretical predictions has demonstrated clearly that the conventionalmodel for this reaction which included the ∆∆ and the Roper resonance excitations via t-channel mesonexchange cannot reproduce the observed energy and angular distributions. At the same time, the newexclusive measurements revealed a generation of the dibaryon resonance D03 in the pn collision, withquantum numbers I(JP ) = 0(3+), the mass mD03

' 2.37 GeV and the narrow width ΓD03 ' 70 MeV.Such a resonance state has been predicted already in 1964 by Dyson and Xuong [3] and since then studiedin numerous works, both theoretical and experimental, but never reached such a level of evidence before.Furthermore, from the exclusive experiments [2], the direct interrelation between the production of theD03 resonance and the ABC effect was clearly established.

We investigated the basic 2π-fusion reaction in the ABC region within a framework of a new model [4]involving the D03-dibaryon production and its subsequent decay via two interfering channels: D03 →d + σ → d + π0π0 and D03 → D12 + π0 → d + π0π0. Here the D12 is the isovector dibaryon withquantum numbers I(JP ) = 1(2+), the mass mD12

' 2.15 GeV and the width ΓD12 ' 110 MeV, whichwas also predicted in [3] and then found in the phase-shift analyses of NN and πd elastic scattering andπd → NN reaction [5]. We shall demonstrate in the talk that the constructive interference of the abovetwo decay channels of the D03 resonance gives a strong near-threshold enhancement in the ππ invariantmass spectrum, i.e. the ABC effect. Herewith, the σ-meson emission from the D03 dibaryon plays acrucial role in reproducing the shape and position of the ABC enhancement and is tightly connected tothe idea of chiral symmetry restoration in dense and excited hadronic systems, such as the D03 state. Inparticular, the σ-meson parameters found by us are in a general agreement with models which predict thechiral symmetry restoration at high excitation energy and/or high density of matter, and they are essen-tially less than those accepted for the free σ meson. So, this result might be considered as an indicationof the partial chiral symmetry restoration in pn, pd, etc., collisions at intermediate energies.

[1] A. Abashian, N.E. Booth, and K.M. Crowe, Phys. Rev. Lett. 5, 258 (1960); 7, 35 (1961).[2] P. Adlarson et al., Phys. Rev. Lett. 106, 242302 (2011); M. Bashkanov et al., Phys. Rev. Lett. 102, 052301(2009).[3] F.J. Dyson and N.-H. Xuong, Phys. Rev. Lett. 13, 815 (1964).[4] M.N. Platonova and V.I. Kukulin, arXiv:1211.0444 [nucl-th].[5] R.A. Arndt, I.I. Strakovsky, R.L. Workman, and D.V. Bugg, Phys. Rev. C 48, 1926 (1993); N. Hoshizaki, Prog.Theor. Phys. 89, 251 (1993).

HN 039


Search for H-dibaryon at J-PARC with a Large Acceptance TPC

H. Sako1, J. K. Ahn2, S. H. Kim2, S. J. Kim2, S. Y. Kim2, A. Ni2, J. Y. Park2, S. Y. Ryu2, S. H. Hwang1, S. Hasegawa1, R. Honda8, Y. Ichikawa1,3, K. Imai1, S. Sato1, K. Shirotori9, S. Sugimura1,3, H. Fujioka3, M. Niiyama3, R. Kiuchi1,4. Tanida1,4. Ieiri5, K. Ozawa5, H. Takahashi5,

T. Takahashi5, K. Nakazawa6, M. Sumihara6, B. Bassalleck7

1 Japan Atomic Energy Agency, 2-4 Shirakata Shirane, Tokai, Ibaraki 319-1195, Japan

2Department of Physics, Pusan National University, Busan 609-735, Korea

3 Department of Physics, Kyoto University, Kyoto 606-8502, Japan

4 Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea

5High Energy Accelerator Research Organization, 1-1 Oho, Tsukuba, Ibaraki 305-0801, Japan

6 Physics Department, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan

7 University of New Mexico, Albuquerque, NM 87131, USA

8 Department of Physics, Tohoku University, 6-3 Aramaki-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan

9 Research Center for Nuclear Physics, Osaka University, 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan


H-dibaryon was proposed as a most stable 6-quark state hadron more than 30 years ago [1]. Since then, many experiments extensively searched for it in various reactions and decay channels, but have never discovered it. Recent lattice QCD calculations [2,3] show H-dibaryon as bound or resonant states close to the threshold. In E224 [4] and E522 [5] experiments at KEK, peaks in invariant mass spectra near the threshold were observed in (K-, K+) reactions, which might indicate H-dibaryon, but the statistics was not significant enough.

Therefore, we proposed an experiment at J-PARC (E42) to search for H-dibaryon. The experiment will measure decay products of , −p in (K−, K+) reaction where decays into −p. We design a large acceptance spectrometer based on a Time Projection Chamber (TPC) under Helmholz dipole magnetic field of 1T. The TPC contains a Cu target inside to cover large acceptance. In order to operate at high K− beam rate of 106 Hz, we adopt GEM (Gas Electron Multiplier) and gating grid wires to suppress positive-ion feedback leading to drift field distortion. We expect to measure 11 K events in the invariant mass resolution of ~1.5 MeV/c2 at the N threshold. The spectrometer has been under R&D, aiming at completion in 2014.

Figure 1: Simulated invariant mass spectrum at E42. The production cross section is assumed to

be 1.0 b/Sr and H-dibaryon mass width is assumed to be zero. [1] R. L. Jaffe, Phys. Rev. Lett. 38, 195 (1977). [2] T. Inoue, et al. (HAL Collaboration), Phys. Rev. Lett. 106, 162002 (2011). [3] S. R. Beane, et al. (NPLQCD Collaboration), Phys. Rev. Lett. 106, 162001 (2011). [4] J. K. Ahn, et al., Phys. Lett. B444, 267 (1998). [5] C. J. Yoon, et al., Phys. Rev. C75, 022201 (2007).

HN 040


Spectroscopy of the Pionic Atoms: Energy Shifts and Widths and ππππ-N

Strong Interaction Effects

A. N. Shakhman1 and I.N. Serga

1

1 Odessa State University - OSENU, P.O. Box 24a,65009, Odessa-9, Ukraine


The work is devoted to calculation of spectra of the pionic atoms and some heavy ions

within ab initio relativistic many-body perturbation theory with account of the relativistic, nuclear,

radiative effects [1]. One of the main purposes is establishment a quantitative link between quality of

the nucleus structure modeling and accuracy of calculating spectral properties. The wave functions

are found from the Klein-Gordon-Fock (pionic atom) or Dirac (usual heavy ion) equations. The

potential includes the SCF ab initio potential, electric and polarization potentials of a nucleus (the

RMF and Gauss models for a charge distribution in a nucleus are used). Data on the energy levels for

some superheavy Li-like ions and shifts and widths for the low-orbit and Rydberg transitions in

pionic atoms (H, He, Cs, Tl, Pb,U) are presented. The received data are compared with available

theoretical and experimental data [2,3]. The strong pion-N interaction corrections to energies are

estimated. It is considered an advanced approach to redefinition of the pion-nucleon

phenomenological optical model potential parameters and increasing an accuracy of the hadronic

transitions energies definition.

In table 1 the data on the transition energies in some pionic atoms (from. Refs. [2,3]): the

measured values form the Berkley, CERN and Virginia laboratories, the theoretical values for the

2 1 , 3 2 , 4 3p s d p f d− − − , 5 4g f− pionic transitions (N

thE 1 - values from the Klein-Gordon-

Fock equation with the pion-nucleus potential [2]; EKGF- values from the Klein-Gordon-Fock

equation with the finite size nucleus potential (our data), N

thE 2 - values from the Klein-Gordon-Fock

equation with the generalized pion-nucleus potential: our data).

Table 1. Transition energies (keV) in the spectra of some pionic atoms

EEXP Eth Element

Berkley CERN Virginia EKGF N

thE 1 N

thE 2

Transition 4f-3d

Cs133 560.5±1.1 562.0±1.5 553.330 561.47 562.12

Transition 5g-4f

Tl204

561.67±0.25 556.562 560.93 561.63

Pb207 575.56±0.25 570.614 575.21 575.78

U238 731.4±1.1 732.0±0.4 730.88±0.75 724.317 729.80 730.52

[1] A.V.Glushkov et al, Nucl. Phys.A734, s21, 2004; Frontiers in Quantum Systems in Chem. and

Phys. (Berlin, Springer) 18, 505, 2008.

[2] R.Deslattes, E.Kessler, P.Indelicato, etal., Rev.Mod.Phys. 75, 35 (2003); D. Anagnostopoulos et

al., Nucl.Instr.Meth.B 205, 9 (2003).

[3] L.I. Menshikov and M.K. Evseev, Phys. Uspekhi 171, 150 (2001).

HN 041

The yield of kaonic hydrogen X-rays in SIDDHARTA experiment

Univ. of Tokyo A, INFN, Laboratori Nazionali di Frascati B, Univ. of Victoria C,Politecnico di Milano D, IFIN-HH E, Stefan Meyer Institut fur subatomare Physik F,INFN Sezione di Roma I and Istituto Superiore di Sanita’ G, RIKEN H,Technische Universitat Munchen I, University of Santiago de Compostela J

H. Shi A, M. Bazzi B, G. Beer C, C. Berucci B ,I, L. Bombelli D, A.M. Bragadireanu B ,E,M. Cargnelli F, A. Clozza B, C. Curceanu B, A. d’Uffizi B, C. Fiorini D, F. Ghio G,C. Guaraldo B, R. S. Hayano A, M. Iliescu B ,E, T. Ishiwatari F, M. Iwasaki H, P. Kienle F ,I,P. Levi Sandri B, V. Lucherini B, J. Marton F, S. Okada B, D. Pietreanu B ,E, K. Piscicchia B,M. Poli Lener B, T. Ponta E, R. Quaglia D, A. Romero Vidal J, E. Sbardella B, A. Scordo B,D.L. Sirghi B ,E, F. Sirghi B ,E, H. Tatsuno B, A. Tudorache E, V. Tudorache E,O. Vazquez Doce I, E. Widmann F, B. Wunschek F, J. Zmeskal F

In the SIDDHARTA experiment at the DAΦNE e+e collider, we measured the K-series X-

rays of kaonic hydrogen atoms with significant improvements over the past experiments[1][2].

Moreover, we also performed the first ever deuterium target study searching for kaonic deu-

terium X-rays.

Based on the data from the measurements of both hydrogen and deuterium targets, we

determined a new set of values for the strong interaction energy-level shift and width of the 1s

atomic state of kaonic hydrogen, published in 2011[3]. The Kp scattering length at threshold

derived directly from this new set of shift and width is consistent with those extrapolated

from the low-energy Kp scattering data. The new results from SIDDHARTA also provide

vital constraints on the QCD chiral SU(3) theory for the low-energy KN interaction[4].

In addition to the shift and width of the 1s state of kaonic hydrogen, we further determined

preliminarily the yield of X-rays per stopped kaon for Kα and all the K-series X-rays of

kaonic hydrogen atom. In this talk, I will present the details of the combined analysis

of the kaonic hydrogen and deuterium spectra, from which the yield of kaonic hydrogen

X-rays is determined. The yield of K-series X-rays will improve the understanding of the

atomic cascade of kaonic hydrogen atom, especially the width of its 2p state which cannot be

measured directly.

Meanwhile, a preliminary upper limit for the yield of kaonic deuterium Kα X-rays as another

conclusion from the combined analysis will also be presented.

[1] M. Iwasaki et al., Phys. Rev. Lett. 78, 3067 (1997);

T. M. Ito et al., Phys. Rev. C 58, 2366 (1998).

[2] G. Beer et al., Phys. Rev. Lett. 94, 212302 (2005).

[3] M. Bazzi, et al., Phys. Lett. B, 704, 113-117, (2011).

[4] Y. Ikeda, T. Hyodo, W. Weise, Nuclear Physics A, 881, 98-114, (2012).

HN 042


Search for 4He-η bound states in dd→ (4He-η)bs → 3Hepπ− anddd→ (4He-η)bs → 3Henπ0 reactions with the WASA-at-COSY facility.

M. Skurzok1, W. Krzemien1, P. Moskal1,2

1 M. Smoluchowski Institute of Physics, Jagiellonian University, 30-059 Cracow, POLAND2 IKP, Forschungszentrum Julich, D-52425 Julich, GERMANY


The existence of η-mesic nuclei in which the η meson is bound in a nucleus by means of the stronginteraction was postulated already in 1986 [1] but it has not been yet confirmed experimentally. Thediscovery of this new kind of an exotic nuclear matter would be very important as it might allow fora better understanding of the η meson structure and its interaction with nucleons [2,3]. The search forη-mesic helium (4He-η) is carried out with high statistics and high acceptance with the WASA detector,installed at the cooler synchrotron COSY of the Research Center Julich [4].The search is conducted via the measurement of the excitation function for selected decay channels ofthe 4He-η system. The kinematics of the reaction is schematically presented in Fig. 1.

Figure 1: Reaction process of the (4He-η)bs production and decay.

The deuteron beam - deuteron target collision leads to the creation of the 4He nucleus bound withthe η meson via strong interaction. The η meson can be absorbed by one of the nucleons inside heliumand may propagate in the nucleus via consecutive excitation of nucleons to the N∗(1525) state until theresonance decays into the pion-proton pair outgoing from the nucleus [5]. The relative angle between pand π− is equal to 180 in the N∗ reference frame and it is smeared by about 30 in the center-of-massframe due to the Fermi motion of the nucleons inside the helium nucleus.

In the experiment, performed in November 2010, two reactions dd → (4He-η)bs → 3Hepπ− anddd → (4He-η)bs → 3Henπ0 were measured with a beam momentum ramped from 2.127GeV/c to2.422GeV/c. The poster will include description of the experimental method and status of the analy-sis.

[1] Q. Haider, L.C. Liu, Phys. Lett. B 172, 257 (1986).[2] T. Inoue, E. Oset, Nucl. Phys. A 710, 354 (2002).[3] S. D. Bass, A. W. Thomas, Acta Phys. Pol. B, 41 (2010).[4] M. Skurzok, P. Moskal, W. Krzemien, Prog. Part. Nucl. Phys. 67, 445 (2012).[5] P. Moskal, arXiv:0909.3979 (2009).

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Study on 6ΛH hypernucleus by the (π−, K+) reaction at J-PARC

H. Sugimura1,2, M. Agnello3,4, J. K. Ahn5, S. Ajimura6, Y. Akazawa7, N. Amano1, K. Aoki8,H. C. Bhang9, M. Endo10, P. Evtoukhovitch11, A. Feliciello4, H. Fujioka1, T. Fukuda12, S. Hasegawa2,

S. Hayakawa10, R. Honda7, K. Hosomi7, S. H. Hwang2, Y. Ichikawa1,2, Y. Igarashi8, K. Imai2,N. Ishibashi10, R. Iwasaki8, C. W. Joo9, R. Kiuchi9,2, J. K. Lee5, J. Y. Lee9, K. Matsuda10,

Y. Matsumoto7, K. Matsuoka10, K. Miwa7, Y. Mizoi12, M. Moritsu1, T. Nagae1, S. Nagamiya2,8,M. Nakagawa10, M. Naruki8, H. Noumi6, R. Ota10, B. J. Roy13, P. K. Saha2, A. Sakaguchi10, H. Sako2,

C. Samanta14, V. Samoilov11, Y. Sasaki7, S. Sato2, M. Sekimoto8, Y. Shimizu12, T. Shiozaki7,K. Shirotori6, T. Soyama10, T. Takahashi8, T. N. Takahashi15, H. Tamura7, K. Tanabe7, T. Tanaka10,

K. Tanida9, A. O. Tokiyasu1, Z. Tsamalaidze11, M. Ukai7, T. O. Yamamoto7, Y. Yamamoto7,S. B. Yang9, K. Yoshida10

1 Department of Physics, Kyoto University, Kyoto 606-8502, Japan2 Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Japan

3 Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, I-10129, Italy4 INFN, Instituto Nazionale di Fisica Nucleare, Sez. di Torino, I-10125, Italy5 Department of Physics, Pusan National University, Busan 609-735, Korea

6 Reaearch Center for Nuclear Physics (RCNP), 10-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan7 Department of Physics Tohoku University, Sendai 980-8578, Japan

8 High Energy Accelerator Research Organization (KEK), Tsukuba 305-0801, Japan9 Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea

10 Department of Physics, Osaka University, Toyonaka, Osaka 560-0043, Japan11 Joint Institute for Nuclear Research, Dubna, Moscow Region 141980, Russia

12 Department of Engineering, Osaka Electro-Communication University, Neyagawa, Osaka 572-8530, Japan13 Nuclear Physics Division, Bhabha Atomic Research Center(BARC), Trombay, Mumbai 400 085, India

14 Physics and Engineering Department, Washington and Lee University, Lexington, VA 24450, USA15 RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan


One of the frontier topics in the strangeness nuclear physics is the study of neutron-richΛ hypernuclei[1].It is expected that the glue like role of theΛ hyperon is critical in nuclei beyond the neutron-drip line.The knowledge of the behavior of hyperons in a neutron-excess environment will significantly affect ourunderstanding of neutron stars, because adding hyperons softens the Equation of State of matter at thecore[2].

Motivated by these issues, we aimed to produce6ΛH hypernucleus because the hypernucleus has the

largest neutron to proton ratio. The study would provide new information on the hypernuclear physicsand the neutron star structures. Recently, the FINUDA collaboration reported observation of 3 candidateevents for the production of the6ΛH hypernucleus[3]. The FINUDA result was suggesting a bound stateof the6

ΛH hypernucleus and was encouraging for us.We carried out the6ΛH production experiment by the (π−,K+) double charge-exchange reaction on

a 6Li target at the pion beam momentum of 1.2GeV/c. Moreover, in order to calibrate the scale of themass orΛ binding energy of the hypernucleus, we measured the12C(π+,K+)12Λ C, p(π−,K+)Σ− andp(π+,K+)Σ+ reactions. In our experiment during December 2012 to January 2013 at the K1.8 beamline,Hadron Hall, J-PARC, the data have been collected for an integrated beam intensity of 1.65×1012 pions.The results of the6ΛH production experiment will be presented and discussed in this conference.

[1] L. Majling, Nucl. Phys.A585211c (1995).[2] M. Baldo, G.F. Burgio, H.J.Schulze, Phys. RevC61, 055801 (2000).[3] M. Agnello et al., FINUDA Collaboration, Phys. Rev. Lett108, 042501 (2012).

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Formation of strange dibaryon X(2265) in p+ p→ K+ +X reaction at Tp

= 2.5 and 2.85 GeVK. Suzuki1, P. Kienle2, M. Maggiora3, T. Yamazaki4,5 for the DISTO collaboration

1 Stefan Meyer Institute for Subatomic Physics, Austrian Academy of Sciences, A-1090, Vienna, Austria2 Excellence Cluster Universe, Technische Universitat Munchen, Garching, Germany

3 Dipartimento di Fisica Generale “A. Avogadro” and INFN, Torino, Italy4 Department of Physics, University of Tokyo, Tokyo, 113-0033 Japan

5 RIKEN Nishina Center, Wako, Saitama, 351-0198 Japan


The so-called X(2265) resonance state has been observed [1] in an exclusive data set of pp→ pΛK+

at Tp = 2.85 GeV of DISTO data with a mass of 2267 MeV/c2 and a width 118 MeV. The X(2265)state has a baryon number 2 and a strangeness −1 and it is possibly a candidate of the (KNN )S=0,I=1/2

kaonic nuclear system, often called K−pp. We studied [2] the energy dependence of the production rateof the X(2265) in the DISTO pp→ pΛK+ data at Tp = 2.5 and 2.85 GeV. If the X(2265) is producedin a similar mechanism as a hyperon production in the pp → pΛK+ then the X(2265) at Tp = 2.5GeV would be produced as much as 33% of the Tp = 2.85 GeV case. However, if the Λ(1405) playsan important role as a door way to the high density kaonic nuclear systems [3], then the production ofthe X(2265) would be strongly suppressed at 2.5 GeV as the beam energy is too close to the productionthreshold of the Λ(1405) and therefore Λ(1405) is merely produced at that energy. We found in the 2.5GeV data no clear sign of a formation of the X(2265). This fits to the latter scenario, supporting that theX(2265) resonance is the long-searched K−pp system.

[1] T. Yamazaki, P. Kienle, M. Maggiora, K. Suzuki et al., Phys. Rev. Lett. 104 (2010) 132502.[2] P. Kienle, M. Maggiora, K. Suzuki, T. Yamazaki et al., Eur. Phys. J. A, 48 (2012) 183.[3] T. Yamazaki and Y. Akaishi, Phys. Rev. C 76 (2007) 045201.

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Missing Mass Spectroscopy of η′ Mesic Nuclei with (p, d) Reaction at GSIY. K. Tanaka1, K. Itahashi2, H. Fujioka3, S. Friedrich4, H. Geissel5, R. S. Hayano1, S. Hirenzaki6,

S. Itoh1, D. Jido7, V. Metag4, H. Nagahiro6, M. Nanova4, T. Nishi1, K. Okochi1, H. Outa2, K. Suzuki8,T. Suzuki1, Y. N. Watanabe1, and H. Weick5

1 Department of Physics, The University of Tokyo, Tokyo, 113-0033, Japan2 Nishina Center for Accelerator-Based Science, RIKEN, Saitama, 351-0198, Japan

3 Department of Physics, Kyoto University, Kyoto, 606-8502, Japan4 II. Physikalisches Institut, Universitat Gießen, D-35392 Gießen, Germany

5 GSI Helmholtzzentrum fur Schwerionenforschung GmbH, D-64291 Darmstadt, Germany6 Department of Physics, Nara Women’s University, Nara 630-8506, Japan

7 Department of Physics, Tokyo Metropolitan Univeristy, Tokyo, 192-0397, Japan8 Stefan-Meyer-Institut fur subatomare Physik, 1090 Vienna, Austria


An η′ meson has a peculiarly large mass, which is theoretically understood as the UA(1) axial anomalyeffect. Since the strength of this effect for the η′ mass is considered to be related to the chiral condensate[1], the η′ mass may be reduced in nuclear medium, where the chiral symmetry is partially restored.According to the Nambu-Jona-Lasinio model calculation, the mass of η′ at normal nuclear density isreduced by about 150 MeV/c2 [2, 3]. Such large mass reduction implies a strong attractive potentialbetween η′ and a nucleus. Thus, η′ meson-nucleus bound states (η′ mesic nuclei) may exist.

As for the decay width, the CBELSA/TAPS collaboration deduced that the absorption width ofthe η′ meson at the nuclear saturation density is around 15 - 25 MeV at the average η′ momentum of1050 MeV/c [4]. This suggests that the decay width of η′ mesic nuclei could be small as well, and theymay be observed as narrow peaks experimentally.

We are planning a missing-mass spectroscopy of η′ mesic nuclei with the 12C(p, d)η′⊗11C reactionat GSI [5]. A 2.5 GeV proton beam of the Heavy Ion Synchrotron (SIS) will be injected to a 12C target.Then, to obtain the missing mass of the reaction, the momentum of the ejectile deuterons will be analyzedby the Fragment Separator (FRS) as a spectrometer. In this inclusive measurement, a signal-to-noise ratiois expected to be very small due to background processes dominated by quasi-free multi-pion production(p+N → d+π’s). This can be overcome by a high-statistics measurement using an intense proton beam(∼ 1010 /spill) and a thick production target (∼ 4 g/cm2). With this condition, if the mass reduction in themedium is around 150 MeV as predicted by the NJL model and the decay width is as small as 20 MeV,peak structures may be observed even in the inclusive spectrum [5].

In this contribution, we will describe the plan of this experiment, and report the feasibility study forseveral mass reductions and decay widths in the medium. Moreover, the status of the preparation for thefirst pilot experiment expected in 2013 - 2014 will be presented.

[1] D. Jido, H. Nagahiro, and S. Hirenzaki, Phys. Rev. C 85 (2012), 032201(R).[2] P. Costa, M. C. Ruivo, and Yu. L. Kalinovsky, Phys. Lett. B 560 (2003), 171.[3] H. Nagahiro and S. Hirenzaki, Phys. Rev. Lett. 94 (2005), 232503; H. Nagahiro, M. Takizawa, andS. Hirenzaki, Phys. Rev. C 74 (2006), 045203.[4] M. Nanova et al., Phys. Lett. B 710 (2012), 600; M. Nanova et al., Prog. Part. Nucl. Phys. 67 (2012), 424.[5] K. Itahashi et al., Letter of Intent for GSI-SIS (2011); K. Itahashi et al., Prog. Theor. Phys. 128, 601 (2012).

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Beam diagnostics for measurements ofantiproton annihilation cross sections at ultra-low energy

K. Todoroki1, H. Aghai-Khozani2, D. Barna1, M. Corradini3,4, M. Hori5, R. Hayano1, T. Kobayashi1,M. Leali3,4, E. Lodi-Rizzini3,4, V. Mascagna3,4, M. Prest6,7, A. Soter5, E. Vallazza8, L. Venturelli3,4,

and N. Zurlo3,4

1 Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033, Japan2 Physics Department, CERN, 1211 Geneva 23, Switzerland

3 Dipartimento di Ingegneria dell’Informazione, Universita di Brescia, 25133 Brescia, Italy4 INFN, Gruppo Collegato di Brescia, 25133 Brescia, Italy

5 Max-Planck-Institut fur Quantenoptik, Hans-Kopfermann-Strasse 1, D-85748 Garching, Germany6 Universita degli Studi dell’Insubria, Italy

7 INFN, Sezione di Milano Bicocca, I-20126 Milano, Italy8 INFN, Sezione di Trieste, I-34127 Trieste, Italy


The ASACUSA collaboration of CERN measured the antiproton-nucleus annihilation cross sectionswith targets of Mylar, Ni, Sn, and Pt at 5.3 MeV of kinetic energy. Their values were consistent with aprediction from a modified black-disk model, which meant antiprotons were so strongly absorbed by nu-clei that elementary processes of quarks inside antiprotons and nuclei could not be observed explicitly[1].Recently we have extended the measurements down to 130 keV, where no experimental data existed anda clear deviation from the black-disk model was expected to be observed[2,3]. The knowledge of thecross section at the very low energy was also important to understand the annihilation process betweenmatter and antimatter which should be occurred at the nucleosynthesis time[2].

The low-energy antiprotons were produced by using the Antiproton Decelerator (AD) and a radio-frequency quadrupole decelerator. As the AD provided a 200-ns-long pulsed beam containing 107

antiprotons, the instantaneous flux arriving at the experiment was too high to resolve individual annihila-tions. This made it difficult to distinguish the signals of annihilation events occurring on the target frombackgrounds caused by spurious annihilations in the surrounding apparatus. A beam profile monitor andelectrostatic quadrupole triplet were therefore developed to ensure that the antiprotons were preciselytuned to the 8-cm-diameter experimental target. The monitor placed at the position of the target was asecondary electron emission detector with an active area of 40 × 40 mm2 and a spacial resolution of4 mm[4]. The electrostatic triplet had a 10-cm-diameter aperture which was large enough to avoid the5-cm-diameter antiproton beam from striking the electrodes and causing background annihilations. Abeam chopper consisting of two parallel electrode plates was also developed to reduce the pulse lengthof the antiproton beam to 100 ns. This allowed the antiproton annihilations to be better separated in timefrom the background. These new instruments are presented, and their performance in connection withthe preliminary experimental results are discussed.

[1] A. Bianconi et al., Phys. Lett. B 704, 461 (2011).[2] H.Aghai-Khozani et al., Eur. Phys. Journ. Plus 127 125 (2012).[3] C.J. Batty, E. Friedman, and A. Gal, Nucl. Phys. A 689 721 (2001).[4] K. Todoroki and M. Hori, J. Instrumentation 7 C02052 (2012).

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Six-body calculations for hyperhydrogen 6H

Sh. Tsiklauri

City University of New York, Borough of Manhattan CC, Science Department, 199 Chambers Str. New York, NY1007


In this work we show results for six body heavy hyperhydrogen 6H using the symmetrized hyperspherical

harmonics basis. We consider a nucleon system interacting through the Volkov potential and a Hyperon nucleon system through the Nijmegen potential [1]. Our calculation for binding B( 6H energy, respect 5H is -3.91 Mev which is in good agreement with experimental result [2] and with earlier calculations [3], but is smaller than prediction of [4]. Our results indicates that N N conversion is ineffective for p state -neutrons in 6H . [1] A. Rijken, V.G.J. Stoks, and Y. Yamamoto, Phys. Rev. C 59 21, (1999). [2]. M. Agnello et al. and A. Gal, Phys. Rev. Lett. 108 042501, (2012). [3]. R.H.Dalitz and R.Levi-Setti, Nuovo Cimento 30, 489, (1963); L.Majling, Nucl. Phys. A 585, 211c (1995). [4]. Theingi, Khin Swe Myint, and Y. Akaishi arXiv:1211.5719v1, (2012).

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p d →3He η reaction beyond threshold energies

N. J. Upadhyay1, B. K. Jain2

1 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing 48824-1321, USA2 MU-DAE Centre for Excellence in Basic Sciences, Mumbai University, Mumbai 400098, India


Experimental data on p d →3He η reaction near threshold energies show an unusual rise in the cross

section and nearly an isotropic angular distribution. These aspects have been understood in the two-step

model including the final state interaction between 3He and η [1]. At higher energies the two-step model

predicts cross sections which peak in backward direction of the eta meson. This is in total variance with

the observed cross sections which peak near to the forward directions. As a first step in the direction

of understanding these data, we present in this contribution calculated angular distributions (shown in

Fig. 1) using the elementary reaction, p p → p p η as a step for eta production in the nucleus. Other

aspects which will affect the calculated cross sections are the FSI and the choice of the bound state wave

functions. At present we have ignored these aspects, and have taken wave functions generated by the

Paris N-N potential [2]. The η-production vertex is described in the Boson-Exchange Model (BEM).

In the description of the elementary reaction, in the literature, both π and ρ-exchanges have been used.

However, the magnitude of the ρ contribution depends on whether one uses γ5σµν or γ5σµ coupling.

The contribution of the former is very small. Also the recently reported polarization data [3] disfavors

the ρ-exchange. Therefore, in the present contribution we have included only one pion-exchange in the

BEM. Results presented in Fig. 1 are for different beam energies well above the threshold. Distributions

peak in the forward hemisphere, though a second peak can also be seen in the backward hemisphere.

Magnitude of cross section increases with the beam energy. Further study of small magnitude of cross

sections is in progress.

0 40 80 120 160

θη (deg.)

0

1

2

3

4

dσ /

dΩ (n

b/sr

) x

10-5

992 MeV (Q = 55.76 MeV)

1002 MeV (Q = 61.25 MeV)

1032 MeV (Q = 77.68 MeV)

Figure 1: Angular distribution of η as a function of angles for different beam energies well above thresh-

old. Corresponding excitation energy, Q(=√s - M3He - Mη) is also shown.

[1] K. P. Khemchandani et al., Phys. Rev. C 76, 069801 (2007);

[2] M. Lacombe et al., Phys. Lett. B 101, 139 (1981);

[3] R. Czyzykiewicz et al., Phys. Rev. Lett. 98, 122003 (2007).

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Structure of low-lying spectrum of cluster Λnα system

B. Vlahovic, V.M. Suslov, I. Filikhin

Department of Physics, North Carolina Central University, Durham, NC 27707 USA


We study structure of energy spectrum of hypothetic 6

ΛHe hyprnuclei using a

Λ++ nα cluster model. The spin doublet )2,1( −−

of 6

ΛHe is interesting for the testing purpose of

the theoretical hyperon-nucleon interaction models [1-3]. The binding energy of the −

1 state (singlet

Λn spin state) of 6

ΛHe has been evaluated in [1] (-0.17 MeV). Theoretical considerations for the

−

2 state (triplet Λn spin state) have been done by Motoba et al. in [2] and Hiyama et al. in [3]. An

indirect prediction for the −

2 state has been given in [4]. In the present work, our cluster approach is

based on the configuration-space Faddeev equations for a system of three non-identical particles.

The analytical continuation method in a coupling constant is applied for calculation of resonance

parameters. The nα interaction is constructed to reproduce the results of R -matrix analysis for nα -

scattering data [5]. An Λα potential was proposed in [6]. For the Λn interaction the s-wave potential

[7] simulating model NSC97f was used. We calculated energies of the low-lying −

1 , −

2 , +

2 , −

0 states. Our predictions for the )2,1( −−

energy gap agree with those obtained in other calculations.

Structure of the 6

ΛHe low-lying spectrum is presented in Fig. 1. Comparing the

6He and

6

ΛHe

spectra one can consider the −

0 state to be a genue hypernuclear state.

This work is supported by NSF CREST (HRD-0833184) and NASA (NNX09AV07A).

Figure 1: Spectra of the 6He (experimental data are from [8]) and

6

ΛH.

[1] L. Majling, Proc. Natl. Conf. on Physics of Few-Body and Quark-Hadronic System (Kharkov,

Ukraine, 1992).

[2] T. Motoba at al. Prog. Theor. Phys. 70, 189 (1983).

[3] E. Hiyama at al. Phys. Rev. C 59, 2351 (1999).

[4] I. Filikhin at al. J. Phys. G: 31, 389 (2005).

[5] K. M. Nollett at al. Phys. Rev. Lett. 99, 022502-4 (2007).

[6] I. Filikhin at al. EPJ Web of Conferences 3, 07004 (2010).

[7] I. Filikhin, A. Gal, Phys. Rev. C 65, 041001R (2002).

[8] http://www.tunl.duke.edu/nucldata/chain/06.shtml

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Charmonium-Nucleus Bound States

A. Yokota1, E. Hiyama2,3, M. Oka1,3

1 Department of Physics, Tokyo Institute of Technology, Meguro 152-8551, Japan2 RIKEN Nishina Center, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan

3 J-PARC Branch, KEK Theory Center, Institute of Particle and Nuclear Studies, High Energy AcceleratorResearch Organization (KEK), 203-1, Shirakata, Tokai, Ibaraki, 319-1106, Japan


It was conjectured [1] that the charmonium (cc) forms bound states in nuclear medium since thecharmonium-nucleon interaction dominated by the QCD color van der Waals interaction is weak butattractive. Recent lattice QCD calculation [2] also suggests that thecc−nucleon scattering lengths cor-respond to weak attractive interactions.

In this study [3], we give a precise calculation of the(cc) − NN three body bound states andJ/ψ−4He bound states by using phenomenological potential model via the Gaussian Expansion Method[4] which was developed by Kyushu Univ. group. We adopt the Gaussian potentials for theηc − NandJ/ψ − N interactions. The relations between the scattering lengthsa and the(cc) − NN bindingenergies are given for bothηc−NN andJ/ψ−NN cases. Our calculations show that scattering lengthsa ≤ −0.95 fm are needed to formηc −NN andJ/ψ −NN bound states. We also calculateJ/ψ−4Hebinding energy and obtain the condition,a ≤ −0.24 fm, for a bound state. The values of the scatteringlengths found in the lattice QCD calculation [2],a ∼ −0.35 fm, seem to be too small to formηc −NNor J/ψ − NN bound states. In contrast, we find thatJ/ψ−4He will form a bound state (B.E.∼ 0.5MeV) with the scattering length from the lattice QCD (see Fig. 1). It is found that the results are notsensitive to the choice of the Gaussian form or its range of the potential.

Thus, we conclude that the charmonium (cc) will form bound states with nuclei ofA ≥ 4, supposingthat the lattice QCD evaluation of the charmonium-nucleon scattering length is reliable.

-5

-4

-3

-2

-1

0

1

-0.7 -0.6 -0.5 -0.4 -0.3 -0.2

-B

[M

eV]

a [fm]

J/ψ-4He

Figure 1:Relation between the binding energyB of J/ψ−4He and theJ/ψ − N scattering lengtha. A boundstate is formed whena ≤ −0.24 fm.

[1] S. J. Brodsky, I. Schmidt and G. F. de Teramond, Phys. Rev. Lett.64, 1011 (1990);[2] T. Kawanai, S. Sasaki, PoSLATTICE 2010, 156 (2010);[3] A. Yokota, E. Hiyama, M. Oka, in preparation;[4] E. Hiyama, Y. Kino, and M. Kamimura, Prog. Part. Nucl. Phys.51, 223 (2003).

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09 - Hadrons in Nuclei

Documents

Book of Abstracts€¦ · 25th International Nuclear Physics Conference (INPC 2013), Firenze (Italy), 2-7 June 2013